User Guide for Cisco Secure Access Control System 5.4
Managing Users and Identity Stores
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Table of Contents

Managing Users and Identity Stores

Overview

Internal Identity Stores

External Identity Stores

Identity Stores with Two-Factor Authentication

Identity Groups

Certificate-Based Authentication

Identity Sequences

Managing Internal Identity Stores

Authentication Information

Identity Groups

Creating Identity Groups

Deleting an Identity Group

Managing Identity Attributes

Standard Attributes

User Attributes

Host Attributes

Configuring Authentication Settings for Users

Creating Internal Users

Deleting Users from Internal Identity Stores

Viewing and Performing Bulk Operations for Internal Identity Store Users

Creating Hosts in Identity Stores

Deleting Internal Hosts

Viewing and Performing Bulk Operations for Internal Identity Store Hosts

Management Hierarchy

Attributes of Management Hierarchy

Configuring AAA Devices for Management Hierarchy

Configuring Users or Hosts for Management Hierarchy

Configuring and Using UserIsInManagement Hierarchy Attribute

Configuring and Using HostIsInManagement Hierarchy Attributes

Managing External Identity Stores

LDAP Overview

Directory Service

Authentication Using LDAP

Multiple LDAP Instances

Failover

LDAP Connection Management

Authenticating a User Using a Bind Connection

Group Membership Information Retrieval

Attributes Retrieval

Certificate Retrieval

Creating External LDAP Identity Stores

Configuring an External LDAP Server Connection

Configuring External LDAP Directory Organization

Deleting External LDAP Identity Stores

Configuring LDAP Groups

Viewing LDAP Attributes

Leveraging Cisco NAC Profiler as an External MAB Database

Enabling the LDAP Interface on Cisco NAC Profiler to Communicate with ACS

Configuring NAC Profile LDAP Definition in ACS for Use in Identity Policy

Troubleshooting MAB Authentication with Profiler Integration

Microsoft AD

Machine Authentication

Attribute Retrieval for Authorization

Group Retrieval for Authorization

Certificate Retrieval for EAP-TLS Authentication

Concurrent Connection Management

User and Machine Account Restrictions

Machine Access Restrictions

Distributed MAR Cache

Dial-In Permissions

Callback Options for Dial-In users

Joining ACS to an AD Domain

Configuring an AD Identity Store

Selecting an AD Group

Configuring AD Attributes

Configuring Machine Access Restrictions

RSA SecurID Server

Configuring RSA SecurID Agents

Creating and Editing RSA SecurID Token Servers

RADIUS Identity Stores

Supported Authentication Protocols

Failover

Password Prompt

User Group Mapping

Groups and Attributes Mapping

RADIUS Identity Store in Identity Sequence

Authentication Failure Messages

Username Special Format with Safeword Server

User Attribute Cache

Creating, Duplicating, and Editing RADIUS Identity Servers

Configuring CA Certificates

Adding a Certificate Authority

Editing a Certificate Authority and Configuring Certificate Revocation Lists

Deleting a Certificate Authority

Exporting a Certificate Authority

Configuring Certificate Authentication Profiles

Configuring Identity Store Sequences

Creating, Duplicating, and Editing Identity Store Sequences

Deleting Identity Store Sequences

Managing Users and Identity Stores

Overview

ACS manages your network devices and other ACS clients by using the ACS network resource repositories and identity stores. When a host connects to the network through ACS requesting access to a particular network resource, ACS authenticates the host and decides whether the host can communicate with the network resource.

To authenticate and authorize a user or host, ACS uses the user definitions in identity stores. There are two types of identity stores:

  • Internal—Identity stores that ACS maintains locally (also called local stores) are called internal identity stores . For internal identity stores, ACS provides interfaces for you to configure and maintain user records.
  • External—Identity stores that reside outside of ACS are called external identity stores . ACS requires configuration information to connect to these external identity stores to perform authentication and obtain user information.

In addition to authenticating users and hosts, most identity stores return attributes that are associated with the users and hosts. You can use these attributes in policy conditions while processing a request and can also populate the values returned for RADIUS attributes in authorization profiles.

Internal Identity Stores

ACS maintains different internal identity stores to maintain user and host records. For each identity store, you can define identity attributes associated with that particular store for which values are defined while creating the user or host records.

You can define these identity attributes as part of identity dictionaries under the System Administration section of the ACS application ( System Administration > Configuration > Dictionaries > Identity ).

Each internal user record includes a password, and you can define a second password as a TACACS+ enable password. You can configure the password stored within the internal user identity store to expire after a particular time period and thus force users to change their own passwords periodically.

Users can change their passwords over the RADIUS or TACACS+ protocols or use the UCP web service. Passwords must conform to the password complexity criteria that you define in ACS.

Internal user records consist of two component types: fixed and configurable.

Fixed components are:

  • Name
  • Description
  • Password
  • Enabled or disabled status
  • Identity group to which users belong

Configurable components are:

  • Enable password for TACACS+ authentication
  • Sets of identity attributes that determine how the user definition is displayed and entered

Cisco recommends that you configure identity attributes before you create users. When identity attributes are configured:

  • You can enter the corresponding values as part of a user definition.
  • They are available for use in policy decisions when the user authenticates.
  • They can be used to populate the values returned for RADIUS attributes in an authorization profile.

Internal user identity attributes are applied to the user for the duration of the user’s session.

Internal identity stores contain the internal user attributes and credential information used to authenticate internal users.

Internal host records are similar to internal user records, except that they do not contain any password information. Hosts are identified by their MAC addresses. For information on managing internal identity stores, see Managing Internal Identity Stores.

External Identity Stores

External identity stores are external databases on which ACS performs authentications for internal and external users. ACS 5.4 supports the following external identity stores:

  • LDAP
  • Active Directory
  • RSA SecurID Token Server
  • RADIUS Identity Server

External identity store user records include configuration parameters that are required to access the specific store. You can define attributes for user records in all the external identity stores except the RSA SecurID Token Server. External identity stores also include certificate information for the ACS server certificate and certificate authentication profiles.

For more information on how to manage external identity stores, see Managing External Identity Stores.

Identity Stores with Two-Factor Authentication

You can use the RSA SecurID Token Server and RADIUS Identity Server to provide two-factor authentication. These external identity stores use an OTP that provides greater security. The following additional configuration options are available for these external identity stores:

  • Identity caching—You can enable identity caching for ACS to use the identity store while processing a request in cases where authentication is not performed. Unlike LDAP and AD, for which you can perform a user lookup without user authentication, the RSA SecurID Token Server and RADIUS Identity Server does not support user lookup.

For example, in order to authorize a TACACS+ request separately from the authentication request, taking into account that it is not possible for the identity store to retrieve the data because authentication is not performed, you can enable identity caching to cache results and attributes retrieved from the last successful authentication for the user. You can use this cache to authorize the request.

  • Treat authentication rejects as—The RSA and RADIUS identity stores do not differentiate between the following results when an authentication attempt is rejected:

Authentication Failed

User Not Found

This classification is very important when you determine the fail-open operation. A configuration option is available, allowing you to define which result must be used.

Identity Groups

Identity groups are logical entities that are defined within a hierarchy and are associated with users and hosts. These identity groups are used to make policy decisions. For internal users and hosts, the identity group is defined as part of the user or host definition.

When external identity stores are used, the group mapping policy is used to map attributes and groups retrieved from the external identity store to an ACS identity group. Identity groups are similar in concept to Active Directory groups but are more basic in nature.

Certificate-Based Authentication

Users and hosts can identify themselves with a certificate-based access request. To process this request, you must define a certificate authentication profile in the identity policy.

The certificate authentication profile includes the attribute from the certificate that is used to identify the user or host. It can also optionally include an LDAP or AD identity store that can be used to validate the certificate present in the request. For more information on certificates and certificate-based authentication, see:

Identity Sequences

You can configure a complex condition where multiple identity stores and profiles are used to process a request. You can define these identity methods in an Identity Sequence object. The identity methods within a sequence can be of any type.

The identity sequence is made up of two components, one for authentication and the other for retrieving attributes.

  • If you choose to perform authentication based on a certificate, a single certificate authentication profile is used.
  • If you choose to perform authentication on an identity database, you can define a list of identity databases to be accessed in sequence until the authentication succeeds. If the authentication succeeds, the attributes within the database are retrieved.

In addition, you can configure an optional list of databases from which additional attributes can be retrieved. These additional databases can be configured irrespective of whether you use password-based or certificate-based authentication.

If a certificate-based authentication is performed, the username is populated from a certificate attribute and this username is used to retrieve attributes from all the databases in the list. For more information on certificate attributes, see Configuring CA Certificates.

When a matching record is found for the user, the corresponding attributes are retrieved. ACS retrieves attributes even for users whose accounts are disabled or whose passwords are marked for change.


Note An internal user account that is disabled is available as a source for attributes, but not for authentication.


For more information on identity sequences, see Configuring Identity Store Sequences.

This chapter contains the following sections:

Managing Internal Identity Stores

ACS contains an identity store for users and an identity store for hosts:

  • The internal identity store for users is a repository of users, user attributes, and user authentication options.
  • The internal identity store for hosts contains information about hosts for MAC Authentication Bypass (Host Lookup).

You can define each user and host in the identity stores, and you can import files of users and hosts.

The identity store for users is shared across all ACS instances in a deployment and includes for each user:

  • Standard attributes
  • User attributes
  • Authentication information

Note ACS 5.4 supports authentication for internal users against the internal identity store only.


This section contains the following topics:

Authentication Information

You can configure an additional password, stored as part of the internal user record that defines the user’s TACACS+ enable password which sets the access level to device. If you do not select this option, the standard user password is also used for TACACS+ enable.

If the system is not being used for TACACS+ enable operations, you should not select this option.

To use the identity store sequence feature, you define the list of identity stores to be accessed in a sequence. You can include the same identity store in authentication and attribute retrieval sequence lists; however, if an identity store is used for authentication, it is not accessed for additional attribute retrieval.

For certificate-based authentication, the username is populated from the certificate attribute and is used for attribute retrieval.

During the authentication process, authentication fails if more than one instance of a user or host exists in internal identity stores. Attributes are retrieved (but authentication is denied) for users who have disabled accounts or passwords that must be changed.

These types of failures can occur while processing the identity policy:

  • Authentication failure; possible causes include bad credentials, disabled user, and so on.
  • User or host does not exist in any of the authentication databases.
  • Failure occurred while accessing the defined databases.

You can define fail-open options to determine what actions to take when each of these failures occurs:

  • Reject—Send a reject reply.
  • Drop—Do not send a reply.
  • Continue—Continue processing to the next defined policy in the service.

The system attribute, AuthenticationStatus , retains the result of the identity policy processing. If you choose to continue policy processing when a failure occurs, you can use this attribute in a condition in subsequent policy processing to distinguish cases where identity policy processing did not succeed.

You can continue processing when authentication fails for PAP/ASCII, EAP-TLS, or EAP-MD5. For all other authentication protocols, the request is rejected and a message to this effect is logged.

Identity Groups

You can assign each internal user to one identity group. Identity groups are defined within a hierarchical structure. They are logical entities that are associated with users, but do not contain data or attributes other than the name you give to them.

You use identity groups within policy conditions to create logical groups of users to which the same policy results are applied. You can associate each user in the internal identity store with a single identity group.

When ACS processes a request for a user, the identity group for the user is retrieved and can then be used in conditions in the rule table. Identity groups are hierarchical in structure.

You can map identity groups and users in external identity stores to ACS identity groups by using a group mapping policy.

Creating Identity Groups

To create an identity group:


Step 1 Select Users and Identity Stores > Identity Groups .

The Identity Groups page appears.

Step 2 Click Create . You can also:

    • Check the check box next to the identity group that you want to duplicate, then click Duplicate .
    • Click the identity group name that you want to modify, or check the check box next to the name and click Edit .
    • Click File Operations to:

Add—Adds identity groups from the import to ACS.

Update—Overwrites the existing identity groups in ACS with the list from the import.

Delete—Removes the identity groups listed in the import from ACS.

    • Click Export to export a list of identity groups to your local hard disk.

For more information on the File Operations option, see Performing Bulk Operations for Network Resources and Users.

The Create page or the Edit page appears when you choose the Create, Duplicate, or Edit option.

Step 3 Enter information in the following fields:

    • Name—Enter a name for the identity group. If you are duplicating an identity group, you must enter a unique name; all other fields are optional.
    • Description—Enter a description for the identity group.
    • Parent—Click Select to select a network device group parent for the identity group.

Step 4 Click Submit to save changes.

The identity group configuration is saved. The Identity Groups page appears with the new configuration. If you created a new identity group, it is located within the hierarchy of the page beneath your parent identity group selection.


 

Related Topics

Deleting an Identity Group

To delete an identity group:


Step 1 Select Users and Identity Stores > Identity Groups .

The Identity Groups page appears.

Step 2 Check one or more check boxes next to the identity groups you want to delete and click Delete .

The following error message appears:

Are you sure you want to delete the selected item/items?

Step 3 Click OK .

The Identity Groups page appears without the deleted identity groups.


 

Related Topic

Managing Identity Attributes

Administrators can define sets of identity attributes that become elements in policy conditions. For information about the ACS 5.4 policy model, see Chapter3, “ACS 5.x Policy Model” During authentication, identity attributes are taken from the internal data store when they are part of a policy condition.

ACS 5.4 interacts with identity elements to authenticate users and obtain attributes for input to an ACS policy.

Attribute definitions include the associated data type and valid values. The set of values depends on the type. For example, if the type is integer , the definition includes the valid range. ACS 5.4 provides a default value definition that can be used in the absence of an attribute value. The default value ensures that all attributes have at least one value.

Related Topics

Standard Attributes

Table 8-1 describes the standard attributes in the internal user record.

 

Table 8-1 Standard Attributes

Attribute
Description

Username

ACS compares the username against the username in the authentication request. The comparison is case-insensitive.

Status

  • Enabled status indicates that the account is active.
  • Disabled status indicates that authentications for the username will fail.

Description

Text description of the attribute.

Identity Group

ACS associates each user to an identity group. See Managing Identity Attributes for information.

User Attributes

Administrators can create and add user-defined attributes from the set of identity attributes. You can then assign default values for these attributes for each user in the internal identity store and define whether the default values are required or optional.

You need to define users in ACS, which includes associating each internal user with an identity group, a description (optional), a password, an enable password (optional), and internal and external user attributes.

Internal users are defined by two components: fixed and configurable. Fixed components consist of these attributes:

  • Name
  • Description
  • Password
  • Enabled or disabled status
  • Identity group to which they belong

Configurable components consist of these attributes:

  • Enable password for TACACS+ authentication
  • Sets of identity attributes that determine how the user definition is displayed and entered

Cisco recommends that you configure identity attributes before you create users. When identity attributes are configured:

  • You can enter the corresponding values as part of a user definition.
  • They are available for use in policy decisions when the user authenticates.

Internal user identity attributes are applied to the user for the duration of the user’s session.

Internal identity stores contain the internal user attributes and credential information used to authenticate internal users (as defined by you within a policy).

External identity stores are external databases on which to perform credential and authentication validations for internal and external users (as defined by you within a policy).

In ACS 5.4, you can configure identity attributes that are used within your policies, in this order:

1. Define an identity attribute (using the user dictionary).

2. Define custom conditions to be used in a policy.

3. Populate values for each user in the internal database.

4. Define rules based on this condition.

As you become more familiar with ACS 5.4 and your identity attributes for users, the policies themselves will become more robust and complex.

You can use the user-defined attribute values to manage policies and authorization profiles. See Creating, Duplicating, and Editing an Internal User Identity Attribute for information on how to create a user attribute.

Host Attributes

You can configure additional attributes for internal hosts. You can do the following when you create an internal host:

  • Create host attributes
  • Assign default values to the host attributes
  • Define whether the default values are required or optional

You can enter values for these host attributes and can use these values to manage policies and authorization profiles. See Creating, Duplicating, and Editing an Internal Host Identity Attribute for information on how to create a host attribute.

Configuring Authentication Settings for Users

You can configure the authentication settings for user accounts in ACS to force users to use strong passwords. Any password policy changes that you make in the Authentication Settings page apply to all internal identity store user accounts. The User Authentication Settings page consists of the following tabs:

  • Password complexity
  • Advanced

To configure a password policy:


Step 1 Choose System Administration > Users > Authentication Settings.

The User Authentication Settings page appears with the Password Complexity and Advanced tabs.

Step 2 In the Password Complexity tab, check each check box that you want to use to configure your user password.

Table 8-2 describes the fields in the Password Complexity tab.

 

Table 8-2 Password Complexity Tab

Option
Description
Applies to all ACS internal identity store user accounts

Minimum length

Required minimum length; the valid options are 4 to 20.

Password may not contain the username

Whether the password may contain the username or reverse username.

Password may not contain ‘cisco’

Check to specify that the password cannot contain the word cisco .

Password may not contain

Check to specify that the password does not contain the string that you enter.

Password may not contain repeated characters four or more times consecutively

Check to specify that the password cannot repeat characters four or more times consecutively.

Password must contain at least one character of each of the selected types

Lowercase alphabetic characters

Password must contain at least one lowercase alphabetic character.

Upper case alphabetic characters

Password must contain at least one uppercase alphabetic character.

Numeric characters

Password must contain at least one numeric character.

Non alphanumeric characters

Password must contain at least one nonalphanumeric character.

Step 3 In the Advanced tab, enter the values for the criteria that you want to configure for your user authentication process. /5-4/user/guide/acsuserguide/users_id_stores.html#92752">Figure 8-1.

Figure 8-1 LDAP Interface Configuration in NAC Profiler

 

Step 5 Click Update Server .

Step 6 Click the Configuration tab and click Apply Changes .

The Update NAC Profiler Modules page appears.

Step 7 Click Update Modules to enable LDAP to be used by ACS.

You must enable the endpoint profiles that you want to authenticate against the Cisco NAC Profiler. For information on how to do this, see Configuring Endpoint Profiles in NAC Profiler for LDAP Authentication.


 

For proper Active Response Events you need to configure Active Response Delay time from your Cisco NAC Profiler UI. For this, choose Configuration > NAC Profiler Modules > Configure Server > Advanced Options > Active Response Delay .

Configuring Endpoint Profiles in NAC Profiler for LDAP Authentication

For the non-802.1X endpoints that you want to successfully authenticate, you must enable the corresponding endpoint profiles in NAC Profiler for LDAP authentication.


Note If the profile is not enabled for LDAP, the endpoints in the profile will not be authenticated by the Cisco NAC Profiler.


To enable the endpoint profiles for LDAP authentication:


Step 1 Log into your NAC Profiler.

Step 2 Choose Configuration > Endpoint Profiles > View/Edit Profiles List .

A list of profiles in a table appears.

Step 3 Click on the name of a profile to edit it.

Step 4 In the Save Profile page, ensure that the LDAP option is enabled by clicking the Yes radio button next to it, if it is not already done as shown in /5-4/user/guide/acsuserguide/users_id_stores.html#89743">Figure 8-2.

Figure 8-2 Configuring Endpoint Profiles in NAC Profiler

 

 

Step 5 Click Save Profile .


 

Configuring NAC Profile LDAP Definition in ACS for Use in Identity Policy

After you install ACS, there is a predefined LDAP database definition for NAC Profiler. This predefined database definition for NAC Profiler contains all the required data for establishing an initial connection. The only exception is the host information, which depends on your specific deployment configuration.

The steps below describe how to configure the host information, verify the connection, and use the profile database in policies.


Note Make sure that ACS NAC Profiler is chosen under Access Policies > Access Services > Default Network Access > Identity.



Note The NAC Profiler template in ACS, available under the LDAP external identity store, works with Cisco NAC Profiler version 2.1.8 and later.


To edit the NAC Profiler template in ACS:


Step 1 Choose Users and Identity Stores > External Identity Stores > LDAP .

Step 2 Click on the name of the NAC Profiler template or check the check box next to the NAC Profiler template and click Edit .

The Edit NAC Profiler definition page appears as shown in Figure 8-3.

Figure 8-3 Edit NAC Profiler Definition - General Page

 

Step 3 Click the Server Connection tab.

The Edit page appears as shown in Figure 8-4.

Figure 8-4 Edit NAC Profiler Definition - Server Connection Page

 

Step 4 In the Primary Server Hostname field, enter the IP address or fully qualified domain name of the Profiler Server, or the Service IP of the Profiler pair if Profiler is configured for High Availability.

Step 5 Click Test Bind to Server to test the connection and verify ACS can communicate with Profiler through LDAP.

A small popup dialog, similar to the one shown in Figure 8-5 appears.

Figure 8-5 Test Bind to Server Dialog Box

For more information, see Creating External LDAP Identity Stores.


Note The default password for LDAP is GBSbeacon. If you want to change this password, refer to the Cisco NAC Profiler Installation and Configuration Guide at the following location:
http://www.cisco.com/en/US/docs/security/nac/profiler/configuration_guide/311/
p_ldap31.html#wp1057155
.


Step 6 If successful, go to the Directory Organization tab.

The Edit page appears as shown in Figure 8-6.

Figure 8-6 Edit NAC Profiler Definition - Directory Organization Page

 

Step 7 Click Test Configuration .

A dialog box as shown in Figure 8-7 appears that lists data corresponding to the Profiler. For example:

    • Primary Server
    • Number of Subjects: 100
    • Number of Directory Groups: 6

Figure 8-7 Test Configuration Dialog Box

 

Number of Subjects —This value maps to the actual subject devices already profiled by the Cisco NAC Profiler (actual devices enabled for Profiler).

After the Profiler receives initial SNMP trap information from the switch, Profiler can poll the switch using SNMP to gather MIB (Management Information Base) information about the switch as well as the connecting endpoint.

After the Profiler has learned about the endpoint (e.g. MAC address, switch port), it adds the endpoint to its database. An endpoint added to the Profiler’s database is considered 1 subject.

Number of Directory Groups —This value maps to the actual profiles enabled for LDAP on Profiler. When already running Profiler on your network, default profiles for endpoints are pre-configured.

However, all profiles are not enabled for LDAP, and must be configured as described in Configuring Endpoint Profiles in NAC Profiler for LDAP Authentication. Note that if setting up Profiler for the first time, once the Profiler is up and running, you will see zero groups initially.


Note The subjects and directory groups are listed if they are less than 100 in number. If the number of subjects or directory groups exceed 100, the subjects and directory groups are not listed. Instead, you get a message similar to the following one:

More than 100 subjects are found.


 

Step 8 Click the Directory Attributes tab if you want to use the directory attributes of subject records as policy conditions in policy rules. See Viewing LDAP Attributes for more information.

Step 9 Choose NAC Profiler as the result (Identity Source) of the identity policy. For more information, see Viewing Identity Policies.

As soon as Endpoint is successfully authenticated from ACS server, ACS will do a CoA (Change of Authorization) and change VLAN. For this, you can configure static VLAN mapping in ACS server. For more information, see Specifying Common Attributes in Authorization Profiles.

When Endpoint is successfully authenticated the following message is displayed on the switch.

ACCESS-Switch# #show authentication sessions
Interface MAC Address Method Domain Status Session ID
Fa1/0/1 0014.d11b.aa36 mab DATA Authz Success 505050010000004A0B41FD15
 


 

For more information on features like Event Delivery Method and Active Response, see the Cisco NAC Profiler Installation and Configuration Guide, Release 3.1 at the following location:

http://www.cisco.com/en/US/docs/security/nac/profiler/configuration_guide/310/p_prof_events31.html

Troubleshooting MAB Authentication with Profiler Integration

To troubleshoot MAB authentication while integrating with NAC Profiler and to verify that the endpoint is successfully authenticated, complete the following steps:


Step 1 Run the following command on the switch which is connected to the endpoint devices:

ACCESS-Switch# show authentication sessions
 

The following output is displayed:

Interface MAC Address Method Domain Status Session ID
Fa1/0/1 0014.d11b.aa36 mab DATA Authz Success 505050010000004A0B41FD15 reject
 

Step 2 Enable debugging for SNMP, AAA, and 802.1X on the switch.

Step 3 Verify the MAB authentication logs in Monitoring and Reports Viewer > Troubleshooting , for failure and success authentications.


 

Microsoft AD

ACS uses Microsoft Active Directory (AD) as an external identity store to store resources such as, users, machines, groups, and attributes. ACS authenticates these resources against AD.

Supported Authentication Protocols

  • EAP-FAST and PEAP—ACS 5.4 supports user and machine authentication and change password against AD using EAP-FAST and PEAP with an inner method of MSCHAPv2 and EAP-GTC.
  • PAP—ACS 5.4 supports authenticating against AD using PAP and also allows you to change AD users password.
  • MSCHAPv1—ACS 5.4 supports user and machine authentication against AD using MSCHAPv1. You can change AD users password using MSCHAPv1 version 2. ACS does not support MS-CHAP MPPE-Keys of a user, but does support MPPE-Send-Key and MPPE-Recv-Key.

Note ACS 5.4 does not support changing user password against AD using MSCHAP version 1.


  • MSCHAPv2—ACS 5.4 supports user and machine authentication against AD using MSCHAPv2. ACS does not support MS-CHAP MPPE-Keys of a user, but does support MPPE-Send-Key and MPPE-Recv-Key.
  • EAP-GTC—ACS 5.4 supports user and machine authentication against AD using EAP-GTC.
  • EAP-TLS—ACS uses the certificate retrieval option introduced in 5.4 to support user and machine authentication against AD using EAP-TLS.

ACS 5.x supports changing the password for users who are authenticated against Active Directory in the TACACS+ PAP/ASCII, EAP-MSCHAP, and EAP-GTC methods. Changing the password for EAP-FAST and PEAP with inner MSCHAPv2 is also supported.

Changing the AD user password using the above methods must comply with the AD password policies. You must check with your AD administrator to determine the complete set of AD password policy rules. The most important AD password policies are:

  • Enforce password history: N passwords are remembered.
  • Maximum password age is N days.
  • Minimum password age is N days.
  • Minimum password length is N characters.
  • Password must meet complexity requirements.

AD uses the “Maximum password age is N days” rule to detect password expiry. All other rules are used during attempts to change a password.

ACS supports these AD domains:

  • Windows Server 2003
  • Windows Server 2003 R2
  • Windows Server 2008
  • Windows Server 2008 R2
  • Windows Server 2012 from patch 2 onwards

ACS machine access restriction (MAR) features use AD to map machine authentication to user authentication and authorization, and sets a the maximal time allowed between machine authentication and an authentication of a user from the same machine.

Most commonly, MAR fails authentication of users whose host machine does not successfully authenticate or if the time between machine and user authentication is greater than the specified aging time. You can add MAR as a condition in authentication and authorization rules as required.

While trying to join ACS to the AD domain, ACS and AD must be time-synchronized. Time in ACS is set according to the Network Time Protocol (NTP) server. Both AD and ACS should be synchronized by the same NTP server. If time is not synchronized when you join ACS to the AD domain, ACS displays a clock skew error. Using the command line interface on your appliance, you must configure the NTP client to work with the same NTP server that the AD domain is synchronized with.

The NTP process restarts automatically when it is down. You can check the NTP process status in two ways:

  • Use the sh app status acs command in CLI interface.
  • Choose Monitoring and Reports > Reports > Catalog > ACS Instance > ACS_Health_Summary in the ACS web interface.

For more information, refer to this URL:

http://www.cisco.com/en/US/docs/net_mgmt/cisco_secure_access_control_system/5.4/command/
reference/cli.html

The ACS appliance uses different levels of caching for AD groups, to optimize performance. AD groups are identified with a unique identifier, the Security Identifier (SID). ACS retrieves the SID that belongs to the user, and uses the cached mapping of the SID with the full name and path of the group. The AD client component caches the mapping for 24 hours. The run-time component of ACS queries the AD client and caches the results, as long as ACS is running.

ACS 5.4 provides AD client troubleshooting tools to troubleshoot AD connectivity issues. You can use the commands adinfo, adcheck, and ldapsearch to troubleshoot AD connectivity issues. ACS provides these CLI commands with the exact same parameters, flags, and conditions that are required for their operation. ACS also redirects the output of these CLI commands to ACSADAgent.log.

For more information on these commands, see CLI Reference Guide for Cisco Secure Access Control System 5.4.


Note To prevent ACS from using the outdated mappings, you should create new AD groups instead of changing or moving the existing ones. If you change or move the existing groups, you have to wait for 24 hours and restart the ACS services to refresh all the cached data.


ACS 5.4 supports certificate authorization.

If there is a firewall between ACS and AD, certain ports need to be opened in order to allow ACS to communicate with AD. The following are the default ports to be opened:

Protocol
Port number

LDAP

389/udp

SMB

445/tcp

KDC

88/(tcp/udp)

Global catalog

3268/tcp

KPASS

464/tcp

NTP

123/udp

DNS

53/(tcp/udp)


Note Dial-in users are not supported by AD in ACS.


This section contains the following topics:

Machine Authentication

Machine authentication provides access to network services to only these computers that are listed in Active Directory. This becomes very important for wireless networks because unauthorized users can try to access your wireless access points from outside your office building.

Machine authentication happens while starting up a computer or while logging in to a computer. Supplicants, such as Funk Odyssey perform machine authentication periodically while the supplicant is running.

If you enable machine authentication, ACS authenticates the computer before a user authentication request comes in. ACS checks the credentials provided by the computer against the Windows user database. If the credentials match, the computer is given access to the network.

Attribute Retrieval for Authorization

You can configure ACS to retrieve user or machine AD attributes to be used in authorization and group mapping rules. The attributes are mapped to the ACS policy results and determine the authorization level for the user or machine.

ACS retrieves user and machine AD attributes after a successful user or machine authentication and can also retrieve the attributes for authorization and group mapping purposes independent of authentication.

Group Retrieval for Authorization

ACS can retrieve user or machine groups from Active Directory after a successful authentication and also retrieve the user or machine group independent of authentication for authorization and group mapping purposes. You can use the AD group data in the authorization and group mapping tables and introduce special conditions to match them against the retrieved groups.

Certificate Retrieval for EAP-TLS Authentication

ACS 5.4 supports certificate retrieval for user or machine authentication that uses EAP-TLS protocol. The user or machine record on AD includes a certificate attribute of binary data type. This can contain one or more certificates. ACS refers to this attribute as userCertificate and does not allow you to configure any other name for this attribute.

ACS retrieves this certificate for verifying the identity of the user or machine. The certificate authentication profile determines the field (SAN, CN, SSN, SAN-Email, SAN-DNS, or SAN-other name) to be used for retrieving the certificates.

After ACS retrieves the certificate, it performs a binary comparison of this certificate with the client certificate. When multiple certificates are received, ACS compares the certificates to check if one of them match. When a match is found, ACS grants the user or machine access to the network.

Concurrent Connection Management

After ACS connects to the AD domain, at startup, ACS creates a number of threads to be used by the AD identity store for improved performance. Each thread has its own connection.

User and Machine Account Restrictions

While authenticating or querying a user or a machine, ACS checks whether:

  • The user account disabled
  • The user locked out
  • The user’s account has expired
  • The query run outside of the specified logon hours

If the user has one of these limitations, the AD1::IdentityAccessRestricted attribute on the AD dedicated dictionary is set to indicate that the user has restricted access. You can use this attribute in group mapping and authorization rules.

Machine Access Restrictions

MAR helps tying the results of machine authentication to user authentication and authorization process. The most common usage of MAR is to fail authentication of users whose host machine does not successfully authenticate. The MAR is effective for all authentication protocols.

MAR functionality is based on the following points:

  • As a result of Machine Authentication, the machine's RADIUS Calling-Station-ID attribute (31) is cached as an evidence for later reference.
  • Administrator can configure the time to live (TTL) of the above cache entries in the AD settings page.
  • Administrator can configure whether or not MAR is enabled in the AD settings page. However for MAR to work the following limitations must be taken into account:

Machine authentication must be enabled in the authenticating protocol settings

The AAA client must send a value in the Internet Engineering Task Force (IETF) RADIUS Calling-Station-Id attribute (31) .

ACS does not replicate the cache of Calling-Station-Id attribute values from successful machine authentications.

ACS do not persevere the cache of Calling-Station-Id attribute . So the content is lost in case you restart ACS or if it crashes. The content is not verified for consistency in case the administrator performs configuration changes that may effect machine authentication.

  • When the user authenticates with either PEAP or EAP-FAST, against AD external ID store then ACS performs an additional action. It searches the cache for the users Calling-Station-Id. If it is found then Was-Machine-Authenticated attribute is set to true on the session context, otherwise set to false.
  • For the above to function correctly, the user authentication request should contain the Calling-Station-Id . In case it does not, the Was-Machine-Authenticated attribute shall be set to false.
  • The administrator can add rules to authorization policies that are based on AD GM attribute and on Machine authentication required attribute. Any rule that contains these two attributes will only apply if the following conditions are met:

MAR feature is enabled

Machine authentication in the authenticating protocol settings is enabled

External ID store is AD

  • When a rule such as the one described above is evaluated, the attributes of AD GM and Was-Machine-Authenticated are fetched from the session context and checked against the rule's condition. According to the results of this evaluation an authorization result is set.
  • Exemption list functionality is supported implicitly (in contrast to ACS 4.x). To exempt a given user group from the MAR the administrator can set a rule such that the column of AD Group consists of the group to exempt and the column of Machine Authentication Required consists of No . See the second rule in the table below for an example.

For example, the administrator will add rules to the authorization policy as follows:

 

AD Group
Machine Authentication Required
ATZ profile

Engineers

Yes

VLAN X

Managers

No

VLAN B

DENY ACCESS

The Engineers' rule is an example of MAR rule that only allows engineers access if their machine was successfully authenticated against windows DB.

The Managers' rule is an example of an exemption from MAR.

Distributed MAR Cache

ACS 5.4 supports the Machine Access Restriction cache per ACS deployment. That is, machine authentication results can be cached among the nodes within the deployment.

MAR Cache Distribution Groups

ACS 5.4 has the option to group ACS nodes in MAR cache distribution groups. This option is used to control the impact of MAR cache distribution operations on ACS performance and memory usage.

A text label is assigned to each ACS node, which is called the MAR cache distribution group value. ACS nodes are grouped based on the MAR cache distribution group value. You can perform MAR cache distribution operations only between the ACS nodes that are assigned to the same MAR cache distribution group.

If the group value of an ACS node is empty, then it is considered as not assigned to any MAR cache distribution group. Such ACS nodes do not participate in any MAR cache distribution operations.

Distributed MAR Cache Operation

The ACS runtime component combines two operations to implement a distributed MAR cache:

  • MAR cache replication with no guaranteed delivery
  • MAR cache distributed search

MAR Cache Replication

The ACS runtime component stores a MAR entry, authenticated Calling-Station-ID , in a MAR cache during machine authentication. At first, ACS saves the MAR entry in the local MAR cache. Then, the ACS runtime component replicates the MAR entry to the ACS nodes that belong to the same MAR cache distribution group.

The replication is performed based on the cache entry replication attempts and the cache entry replication timeouts that are configured in the ACS web interface.

The replication operation is performed in the background and does not interrupt or delay the user authentication that triggered this replication.

MAR Cache Distributed Search

At first, ACS searches for the MAR entry in the local MAR cache. If the MAR entry is not found in the local MAR cache, then ACS queries the ACS nodes that are assigned to the same MAR cache distribution group.

The distributed search is performed based on the cache entry query attempts and cache entry query timeouts that are configured in the ACS web interface. The MAR entry search is also delayed until the first successful response from any of the queried ACS nodes, up to the maximum of the configured cache entry query timeout period.

Distributed MAR Cache Output in ACS View:

  • 24422 - ACS has confirmed previous successful machine authentication for user in Active Directory.
  • 24423 - ACS has not been able to confirm previous successful machine authentication for user in Active Directory.
  • 24701 - ACS peer has confirmed previous successful machine authentication for user in Active Directory.
  • 24702 - ACS peers have not confirmed previous successful machine authentication for user in Active Directory.

Distributed MAR Cache Reliability

The ACS runtime component combines two operations to implement the distributed MAR cache, in order to ensure strong reliability.

The distributed search option provides a fallback facility when the replication messages for some reason are not delivered. In this case, you can find the MAR cache entry on the ACS node that performs the machine authentication or on any one of the ACS nodes from the same MAR cache distribution group. The distributed search option also provides a fallback facility when the ACS node that performs the machine authentication is restarted.

In this case, also, you can find the MAR cache entry in any one of the ACS nodes from the same MAR cache distribution group.

You lose the MAR cache entry when you restart all of the ACS nodes in the ACS deployment.

Dial-In Permissions

The dial-in permissions of a user are checked during authentications or queries from Active Directory. The dial-in check is supported only for user authentications and not for machines, in the following authentication protocols:

  • PAP
  • MSCHAPv2
  • EAP-FAST
  • PEAP
  • EAP-TLS.

The following results are possible:

  • Allow Access
  • Deny Access
  • Control Access through Remote Access Policy. This option is only available for Windows 2000 native domain, Windows server 2003 domain.
  • Control Access through NPS Network Policy. This is the default result. This option is only available for Windows server 2008 and Windows 2008 R2 domains.

Callback Options for Dial-In users

If the callback option is enabled, the server calls the caller back during the connection process. The phone number that is used by the server is set either by the caller or the network administrator.

The possible callback options are:

  • No callback
  • Set by Caller (routing and remote access service only). This option can be used to define a series of static IP routes that are added to the routing table of the server running the Routing and Remote Access service when a connection is made.
  • Always callback to (with an option to set a number). This option can be used to assign a specific IP address to a user when a connection is made

The callback attributes should be returned on the RADIUS response to the device.

Dial-In Support Attributes

The user attributes on Active Directory are supported on the following servers:

  • Windows Server 2003
  • Windows Server 2003 R2
  • Windows Server 2008
  • Windows Server 2008 R2

ACS does not support Dial-in users on Windows 2000.

ACS Response

If you enable the dial-in check on ACS Active Directory and the user's dial-in option is 'Deny Access' on Active Directory, the authentication request is rejected with a message in the log, indicating that dial-in access is denied. If a user fails an MSCHAP v1/v2 authentication if the dial-in is not enabled, ACS should set on the EAP response a proper error code (NT error = 649).

In case that the callback options are enabled, the ACS RADIUS response contains the returned Service Type and Callback Number attributes as follows:

  • If callback option is Set by Caller or Always Callback To, the service-type attribute should be queried on Active Directory during the user authentication. The service-type can be the following:

3 = Callback Login

4 = Callback Framed

9 = Callback NAS Prompt

This attribute should be returned to the device on Service-type RADIUS attribute. If ACS is already configured to return service-type attribute on the RADIUS response, the service-type value queried for the user on Active Directory replaces it.

  • If the Callback option is Always Callback To, the callback number should also be queried on the Active Directory user. This value is set on the RADIUS response on the Cisco-AV-Pair attribute with the following values:

cisco-av-pair=lcp:callback-dialstring=[callback number value]

cisco-av-pair=Shell:callback-dialstring=[callback number value]

cisco-av-pair=Slip:callback-dialstring=[callback number value]

cisco-av-pair=Arap:callback-dialstring=[callback number value]

The callback number value is also returned on the RADIUS response, using the RADIUS attribute CallbackNumber (#19).

  • If callback option is Set by Caller, the RADIUS response contains the following attributes with no value:

cisco-av-pair=lcp:callback-dialstring=

cisco-av-pair=Shell:callback-dialstring=

cisco-av-pair=Slip:callback-dialstring=

cisco-av-pair=Arap:callback-dialstring=

Joining ACS to an AD Domain

In ACS 5.4, you can join the ACS nodes from same deployment to different AD domains. However, each node can be joined to a single AD domain. The policy definitions of those ACS nodes are not changed and that uses the same AD identity store.

For information on how to configure an AD identity store, see Configuring an AD Identity Store.


Note The Windows AD account, which joins ACS to the AD domain, can be placed in its own organizational unit (OU). It resides in its own OU either when the account is created or later on, with a restriction that the appliance name must match the name of the AD account.



Note ACS does not support user authentication in AD when a user name is supplied with an alternative UPN suffix configured in OU level. The authentication works fine if the UPN suffix is configured in domain level.


Related Topics

Machine Authentication

Configuring an AD Identity Store

The AD settings are not displayed by default, and they are not joined to an AD domain when you first install ACS. When you open the AD configuration page, you can see the list of all ACS nodes in the distributed deployment.

When you configure an AD identity store, ACS also creates the following:

  • A new dictionary for that store with two attributes: the ExternalGroup attribute and another attribute for any attribute that is retrieved from the Directory Attributes page.
  • A new attribute, IdentityAccessRestricted. You can manually create a custom condition for this attribute.
  • A custom condition for group mapping from the ExternalGroup attribute—the custom condition name is AD1:ExternalGroups—and another custom condition for each attribute that is selected in the Directory Attributes page (for example, AD1:cn).

You can edit the predefined condition name, and you can create a custom condition from the Custom condition page. See Creating, Duplicating, and Editing a Custom Session Condition.


Note When you upgrade ACS to ACS 5.4 version using the Reimaging and Upgrading an ACS Server method, if you restore a configuration in which the AD is defined, you need to join ACS manually to the AD domain. See Installation and Upgrade Guide for Cisco Secure Access Control System for more information on upgrade methods.



Note When you upgrade ACS to ACS 5.4 using the Upgrading an ACS Server Using Application Upgrade Bundle method, if you have ACS joined to AD already, ACS remains connected to AD after the application upgrade.


To authenticate users and join ACS with an AD domain:


Step 1 Select Users and Identity Stores > External Identity Stores > Active Directory .

The Active Directory page appears.

The AD configuration page acts as a central AD management tool for all ACS nodes. You can perform the join and test connection operations against a single ACS node or multiple ACS nodes on this page. You can also view the join results of all ACS nodes in the deployment at a single glance.

Step 2 Modify the fields in the General tab as described in Table 8-10 .

 

Table 8-10 Active Directory: General Page

Option
Description
Connection Details

Join/Test Connection

Click to join or test the ACS connection with the AD domain for the given user, domain, and password entered. See Joining Nodes to an AD Domain.

Leave

Click to disconnect a single node or multiple nodes from the AD domain for the given user, domain, and password entered. See Disconnecting Nodes from the AD Domain

End User Authentication Settings

Enable password change

Click to allow the password to be changed.

Enable machine authentication

Click to allow machine authentication.

Enable dial-in check

Click to examine the user’s dial-in permissions during authentication or query. The result of the check can cause a reject of the authentication in case the dial-in permission is denied.

The result is not stored on the AD dictionary.

Enable callback check for dial-in clients

Click to examine the user’s callback option during authentication or query. The result of the check is returned to the device on the RADIUS response.

The result is not stored on the AD dictionary.

Connectivity Status

Joined to Domain

( Display only .) After you save the configuration (by clicking Save Changes ), this shows the domain name with which ACS is joined.

Connectivity Status

( Display only .) After you save the configuration (by clicking Save Changes ), this shows the connection status of the domain name with which ACS is joined.

Step 3 Click:

    • Save Changes to save the configuration.
    • Discard Changes to discard all changes.
    • If AD is already configured and you want to delete it, click Clear Configuration after you verify the following:

There are no policy rules that use custom conditions based on the AD dictionary.

The AD is not chosen as the identity source in any of the available access services.

There are no identity store sequences with the AD.

The Active Directory configuration is saved. The Active Directory page appears with the new configuration.


 


Note The AD connector configuration is affected (and sometimes gets disconnected) when there is a slow response from the server while you test the ACS connection with the AD domain. However the configuration works fine with the other applications.



Note Due to NETBIOS limitations, ACS hostnames must contain less than or equal to 15 characters.


Joining Nodes to an AD Domain

To join a single node or multiple nodes to an AD Domain, complete the following steps:


Step 1 Select Users and Identity Stores > External Identity Stores > Active Directory.

The Active Directory page appears.

Step 2 Select a single node or multiple nodes and click Join/Test Connection.

The Join/Test Connection page appears.

Step 3 Complete the fields in the Join/Test Connection page as described in Table 8-11 .

Table 8-11 Join/Test Connection Page

Option
Description

Active Directory Domain Name

Name of the AD domain to which you want to join ACS.

Username

Enter the username of a predefined AD user. An AD account which is required for the domain access in ACS, should have either of the following:

  • Add workstations to the domain user in the corresponding domain.
  • Create Computer Objects or Delete Computer Objects permission on corresponding computers container where ACS machine's account is precreated (created before joining ACS machine to the domain).

Cisco recommends that you disable the lockout policy for the ACS account and configure the AD infrastructure to send alerts to the administrator if a wrong password is used for that account. This is because, if you enter a wrong password, ACS will not create or modify its machine account when it is necessary and therefore possibly deny all authentications.

Password

Enter the user password. The password should have a minimum of 8 characters, using a combination of at least one lower case letter, one upper case letter, one numeral, and one special character. All special characters are supported.

Step 4 Click:

    • Join to join the selected nodes to the AD domain. The status of the nodes are changed according to the join results.
    • Test Connection to test the connection to ensure that the entered credentials are correct and the AD domain is reachable. A message appears informing you whether the AD server is routable within the network and also authenticating the given AD username and password. The Test Connection results are displayed in a separate dialog box as a table.
    • Cancel to cancel the connection.


 

Disconnecting Nodes from the AD Domain

To disconnect a single node or multiple nodes from an AD Domain, complete the following steps:


Step 1 Select Users and Identity Stores > External Identity Stores > Active Directory .

The Active Directory page appears.

Step 2 Select a single node or multiple nodes and click Leave.

The Leave Connection page appears.

Step 3 Complete the fields in the Leave Connection page as described in Table 8-12

Table 8-12 Leave Connection Page

Option
Description

Username

Enter the username of a predefined AD user. An AD account which is required for the domain access in ACS, should have either of the following:

  • Add workstations to the domain user in the corresponding domain.
  • Create Computer Objects or Delete Computer Objects permission on corresponding computers container where ACS machine's account is precreated (created before joining ACS machine to the domain).

Cisco recommends that you disable the lockout policy for the ACS account and configure the AD infrastructure to send alerts to the administrator if a wrong password is used for that account. This is because, if you enter a wrong password, ACS will not create or modify its machine account when it is necessary and therefore possibly deny all authentications.

Password

Enter the user password.

Do not try to remove machine account

Check this check box to disconnect the selected nodes from the AD domain, when you do not know the credentials or have any DNS issues.

This operation disconnects the node from the AD domain and leaves an entry for this node in the database. Only administrators can remove this node entry from the database.

Step 4 Click:

    • Leave to disconnect the selected nodes from AD domain.
  • Cancel to cancel the operation.


 


Note Administrators can perform operations like join, leave, or test connection from the secondary server. When you perform these operations from the secondary server, it affects only the secondary server.


Related Topics

Selecting an AD Group

Use this page to select groups that can then be available for policy conditions.


Note To select groups and attributes from an AD, ACS must be connected to that AD.



Step 1 Select Users and Identity Stores > External Identity Stores > Active Directory , then click the Directory Groups tab.

The Groups page appears. The Selected Directory Groups field lists the AD groups you selected and saved. The AD groups you selected in the External User Groups page are listed and can be available as options in group mapping conditions in rule tables.

If you have more groups in other trusted domains or forests that are not displayed, you can use the search filter to narrow down your search results. You can also add a new AD group using the Add button. \


Note ACS 5.4 does not retrieve domain local groups. It is not recommended to use domain local groups in ACS policies. The reason is that the membership evaluation in domain local groups can be time consuming. So, by default, the domain local groups are not evaluated.


Step 2 Click Select to see the available AD groups on the domain (and other trusted domains in the same forest).

The External User Groups dialog box appears displaying a list of AD groups in the domain, as well as other trusted domains in the same forest.

If you have more groups that are not displayed, use the search filter to refine your search and click Go .

Step 3 Enter the AD groups or select them from the list, then click OK .

To remove an AD group from the list, click an AD group, then click Deselect .

Step 4 Click:

    • Save Changes to save the configuration.
    • Discard Changes to discard all changes.
    • If AD is already configured and you want to delete it, click Clear Configuration after you verify that there are no policy rules that use custom conditions based on the AD dictionary.


 


Note When configuring the AD Identity Store on ACS 5.x, the security groups defined on Active Directory are enumerated and can be used, but distribution groups are not shown. Active Directory Distribution groups are not security-enabled and can only be used with e-mail applications to send e-mail to collections of users. Please refer to Microsoft documentation for more information on distribution groups.



Note Logon authentication may fail on Active Directory when ACS tries to authenticate users who belong to more than 1015 groups in external identity stores. This is due to the Local Security Authentication (LSA) limitations in Active Directory.


Configuring AD Attributes

Use this page to select attributes that can then be available for policy conditions.


Step 1 Select Users and Identity Stores > External Identity Stores > Active Directory , then click the Directory Attributes tab.

Step 2 Complete the fields in the Active Directory: Attributes page as described in Table 8-13 :

 

Table 8-13 Active Directory: Attributes Page

Option
Description

Name of example Subject to Select Attributes

Enter the name of a user or computer found on the joined domain. You can enter the user’s or the computer’s CN or distinguished name.

The set of attributes that are displayed belong to the subject that you specify. The set of attributes are different for a user and a computer.

Select

Click to access the Attributes secondary window, which displays the attributes of the name you entered in the previous field.

Attribute Name List—Displays the attributes you have selected in the secondary Selected Attributes window. You can select multiple attributes together and submit them.

Attribute Name

  • Do one of the following:

Enter the name of the attribute.

You can also select an attribute from the list, then click Edit to edit the attribute.

  • Click Add to add an attribute to the Attribute Name list.

Type

Attribute types associated with the attribute names. Valid options are:

  • String
  • Unsigned Integer 64
  • IP Address—This can be either an IPv4 or IPv6 address.

Default

Specified attribute default value for the selected attribute:

  • String—Name of the attribute.
  • Unsigned Integer 64—0.
  • IP Address—No default set.

Policy Condition Name

Enter the custom condition name for this attribute. For example, if the custom condition name is AAA , enter AAA in this field and not AD1: att_name .

Select Attributes Secondary Window

Available from the Attributes secondary window only.

Search Filter

Specify a user or machine name.

  • For user names, you can specify distinguished name, SAM, NetBios, or UPN format.
  • For machine names, you can specify one of the following formats: MACHINE$, NETBiosDomain\MACHINE$, host/MACHINE, or host/machine.domain. You can specify non-English letters for user and machine names.

Attribute Name

The name of an attribute of the user or machine name you entered in the previous field.

Attribute Type

The type of attribute.

Attribute Value

The value of an attribute for the specified user or machine.

Step 3 Click:

    • Save Changes to save the configuration.
    • Discard Changes to discard all changes.
    • If AD is already configured and you want to delete it, click Clear Configuration after you verify that there are no policy rules that use custom conditions based on the AD dictionary.


 

Configuring Machine Access Restrictions

To configure the Machine Access Restrictions, complete the following steps:


Step 1 Select Users and Identity Stores > External Identity Stores > Active Directory , then click the Machine Access Restrictions tab.

Step 2 Complete the fields in the Active Directory: Machine Access Restrictions page as described in Table 8-14 .

 

Table 8-14 Active Directory: Machine Access Restrictions Page

Option
Description

Enable Machine Access Restrictions

Check this check box to enable the Machine Access Restrictions controls in the web interface. This ensures that the machine authentication results are tied to user authentication and authorization. If you enable this feature, you must set the Aging time.

Aging time (hours)

Time after a machine was authenticated that a user can be authenticated from that machine. If this time elapses, user authentication fails. The default value is 6 hours. The valid range is from 1 to 8760 hours.

MAR Cache Distribution

Cache entry replication timeout

Enter the time in seconds after which the cache entry replication gets timed out. The default value is 5 seconds. The valid range is from 1 to 10.

Cache entry replication attempts

Enter the number of times ACS has to perform MAR cache entry replication. The default value is 2. The valid range is from 0 to 5.

Cache entry query timeout

Enter the time in seconds after which the cache entry query gets timed out. The default value is 2 seconds. The valid range is from 1 to 10.

Cache entry query attempts

Enter the number of times that ACS has to perform the cache entry query. The default value is 1. The valid range is from 0 to 5.

Node

Lists all the nodes that are connected to this AD domain.

Cache Distribution Group

Enter the Cache Distribution Group of the selected node. This accepts any text string to a maximum of 64 characters.

Step 3 Click:

    • Save Changes to save the configuration.
    • Discard Changes to discard all changes.
    • If AD is already configured and you want to delete it, click Clear Configuration after you verify that there are no policy rules that use custom conditions that are based on the AD dictionary.


 

AD Deployments with Users Belonging to Large Number of Groups

In ACS 5.3, when you move between AD domains, the user authentications show a timeout error if the user belongs to a large number of groups (more than 50 groups). But, the subsequent authentication of the same user or another user belongs to the same group works properly. This is due to the adclient.get.builtin.membership parameter in ACS AD agent configuration. This parameter, when set as true, performs a lot of additional requests and takes a lot of time for the users who belong to large number of groups. You can observe that the AD built-in groups are not available for usage in ACS policies after the adclient.get.builin.membership parameter is set as true. So, to overcome this issue, you should set the adclient.get.builtin.membership parameter as false.

To set adclient.get.builin.membership parameter, perform the following steps in ACS CLI:


Step 1 Log into ACS CLI in configuration mode.

Step 2 Enter the following commands:

acs-config

ad-agent-configuration adclient.get. builtin.membership false


 


Note The first authentication of a user belongs to the large number of groups may fail with a timeout error. But, the subsequent authentications of the same user or another user belongs to the same group works properly.


Joining ACS to Domain Controllers

When ACS needs to connect to a domain controller or a global catalog, it sends SRV requests to the configured DNS servers to find out the available list of domain controllers for a domain and the global catalogs for a forest.

If the Active Directory configuration on ACS machine is assigned to a subnet, which in turn is assigned to a site, then ACS sends the DNS queries scoped to the site. That is the DNS server is supposed to return the domain controllers and the global catalogs serving that particular site to which the subnet is assigned to.

If the ACS machine is not assigned to a site, then ACS does not send the DNS queries scoped to the site. That is the DNS server is supposed to return all available domain controllers and global catalogs with no regard to the sites.

ACS iterates the available list of domain controllers or global catalogs and tries to establish the connection according to the order of the domain controllers or the global catalogs in the DNS response received from the DNS server.

RSA SecurID Server

ACS supports the RSA SecurID server as an external database. RSA SecurID two-factor authentication consists of the user’s personal identification number (PIN) and an individually registered RSA SecurID token that generates single-use token codes based on a time code algorithm.

A different token code is generated at fixed intervals (usually each at 30 or 60 seconds). The RSA SecurID server validates this dynamic authentication code. Each RSA SecurID token is unique, and it is not possible to predict the value of a future token based on past tokens.

Thus when a correct token code is supplied together with a PIN, there is a high degree of certainty that the person is a valid user. Therefore, RSA SecurID servers provide a more reliable authentication mechanism than conventional reusable passwords.

You can integrate with RSA SecurID authentication technology in any one of the following ways:

  • Using the RSA SecurID agent—Users are authenticated with username and passcode through the RSA’s native protocol.
  • Using the RADIUS protocol—Users are authenticated with username and passcode through the RADIUS protocol.

RSA SecurID token server in ACS 5.4 integrates with the RSA SecurID authentication technology by using the RSA SecurID Agent.

Create an Agent Record (sdconf.rec)

To configure an RSA SecurID token server in ACS 5.4, the ACS administrator requires the sdconf.rec file. The sdconf.rec file is a configuration record file that specifies how the RSA agent communicates with the RSA SecurID server realm.

In order to create the sdconf.rec file, the RSA SecurID server administrator should add the ACS host as an Agent host on the RSA SecurID server and generate a configuration file for this agent host.

Reset the Node Secret (securid)

After the agent initially communicates with the RSA SecurID server, the server provides the agent with a node secret file called securid. Subsequent communication between the server and the agent relies on exchanging the node secret to verify the other’s authenticity.

At times, you might have to reset the node secret. To reset the node secret:

  • The RSA SecurID server administrator must uncheck the Node Secret Created check box on the Agent Host record in the RSA SecurID server.
  • The ACS administrator must remove the securid file from ACS.

Override Automatic Load Balancing

RSA SecurID Agent automatically balances the requested loads on the RSA SecurID servers in the realm. However, you do have the option to manually balance the load. You can specify which server each of the agent hosts must use and assign a priority to each server so that the agent host directs authentication requests to some servers more frequently than others.

You must specify the priority settings in a text file and save it as sdopts.rec, which you can then upload to ACS.

Manually Intervene to Remove a Down RSA SecurID Server

When an RSA SecurID server is down, the automatic exclusion mechanism does not always work quickly. To speed up this process, you can remove the sdstatus.12 file from ACS.

Creating and Editing RSA SecurID Token Servers

ACS 5.4 supports RSA SecurID Token Servers for authenticating users for the increased security that one-time passwords provide. RSA SecurID token servers provide two-factor authentication to ensure the authenticity of users.

To authenticate users against an RSA identity store, you must first create an RSA SecurID Token Server in ACS and configure the realm, ACS instance, and advanced settings.

ACS 5.4 supports only one RSA realm. You can configure the settings for the RSA realm. A single realm can contain many ACS instances.


Note You must obtain the sdconf.rec file from the RSA SecurID server administrator and store it in ACS.


To create or edit an RSA SecurID token server:


Step 1 Select Users and Identity Stores > External Identity Stores > RSA SecurID Token Servers .

The RSA SecurID Token Servers page appears.

Step 2 Click Create .

You can also click the identity store name that you want to modify, or check the box next to the name and click Edit .

Step 3 Complete the fields in the RSA Realm Settings tab as described in Table 8-15 .

 

Table 8-15 RSA Realm Settings Tab

Option
Description
General

Name

Name of the RSA realm.

Description

(Optional) The description of the RSA realm.

Server Connection

Server Timeout n seconds

ACS waits for n seconds to connect to the RSA SecurID token server before timing out.

Reauthenticate on Change PIN

Check this check box to reauthenticate on change PIN.

Realm Configuration File

Import new ‘sdconf.rec’ file

Click Browse to select the sdconf.rec file from your machine.

Node Secret Status

Once the user is first authenticated against RSA SecurID Token Server, the Node Secret Status is shown as Created .

 

Step 4 Click the ACS Instance Settings tab. See Configuring ACS Instance Settings for more information.

 

Step 5 Click the Advanced tab. See Configuring Advanced Options for more information.

Step 6 Click Submit to create an RSA SecurID store.

The RSA SecurID Token Server page appears with the configured servers.


 

Related Topics:

Configuring ACS Instance Settings

The ACS Instance Settings tab appears with the current list of ACS instances that are active in the system. You cannot add or delete these entries. However, you can edit the available RSA Realm settings for each of these ACS instances.

. Table 8-16 describes the fields in the ACS Instance Settings tab.

 

Table 8-16 ACS Instance Settings Tab

Option
Description

ACS Instance

Name of the ACS instance.

Options File

Name of the options file.

Node Secret Status

Status of Node Secret. This can be one of the following:

  • Created
  • Not created

You can edit the settings of the ACS instances that are listed on this page. To do this:


Step 1 Check the check box next to the ACS instance that you want to edit and click Edit .

The ACS instance settings dialog box appears. This dialog box contains the following tabs:

Step 2 Click OK.


 

Related Topics

Editing ACS Instance Settings

You can edit the ACS instance settings to:

Enable the RSA options file

You can enable the RSA options file ( sdopts.rec ) on each ACS instance to control routing priorities for connections between the RSA agent and the RSA servers in the realm.

Table 8-17 describes the fields in the RSA Options File tab.

 

Table 8-17 RSA Options File Tab

Option
Description

The RSA options file (sdopts.rec) may be enabled on each ACS instance to control the routing priorities for connections between the RSA agent and the RSA servers in the realm. For detailed description of the format of the sdopts.rec, please refer to the RSA Documentation.

Use the Automatic Load Balancing status maintained by the RSA Agent

Choose this option to use the automatic load balancing status that the RSA agent maintains.

Override the Automatic Load Balancing status with the sdopts.rec file selected below

Choose this option to use the automatic load balancing status that is specified in the sdopts.rec file.

Current File

Lists the sdopts.rec file that is chosen currently.

Timestamp

Time when sdopts.rec file was last modified.

File Size

Size of the sdopts.rec file.

Import new ‘sdopts.rec’ file

Click Browse to import the new sdopts.rec file from your hard drive.

Note Changes will not take effect until the page which launched this popup is submitted.

Do one of the following:

  • Click OK to save the configuration.
  • Click the Reset Agent Files tab to reset the secret key information or the status of active and inactive servers in the realm.

Related Topics

Reset Agent Files

Use this page to reset the following:

  • Node Secret key file, to ensure that communication with the RSA servers is encrypted.
  • Status of the servers in the realm.

Step 1 Choose either of the following options:

    • To reset node secret on the agent host, check the Remove securid file on submit check box.

If you reset the node secret on the agent host, you must reset the agent host’s node secret in the RSA server.

    • To reset the status of servers in the realm, check the Remove sdstatus.12 file on submit check box.

Step 2 Click OK .


 

Related Topics

Configuring Advanced Options

Use this page to do the following:

  • Define what an access reject from an RSA SecurID token server means to you.
  • Enable identity caching—Caching users in RSA is similar to caching users in Radius Token with the logic and the purpose of the caching being the same. The only difference is that in RSA there is no attribute retrieval for users and therefore no caching of attributes. The user who is authenticated is cached, but without any attributes.

To configure advanced options for the RSA realm:


Step 1 Do one of the following:

    • Click the Treat Rejects as Authentication failed radio button—ACS to interprets this as an authentication reject from an RSA SecurdID store as an authentication failure.
    • Click the Treat Rejects as User not found radio button—ACS interprets this as an authentication reject from an RSA SecurID store as “user not found.”

Step 2 Enable identity caching to allow ACS to process requests that are not authenticated through the RSA server.

The results obtained from the last successful authentication are available in the cache for the specified time period.

Step 3 Check the Enable identity caching check box.

Step 4 Enter the aging time in minutes.

The identity cache stores the results of a successful login only for the time period specified here.

Step 5 Click Submit .


 

Related Topics

RADIUS Identity Stores

RADIUS server is a third-party server that supports the RADIUS interface. RADIUS identity store, which is part of ACS, connects to the RADIUS server.

RADIUS servers are servers that come with a standard RADIUS interface built into them and other servers that support the RADUIS interface. ACS 5.4 supports any RADIUS RFC 2865-compliant server as an external identity store. ACS 5.4 supports multiple RADIUS token server identities.

For example, the RSA SecurID server and SafeWord server. RADIUS identity stores can work with any RADIUS Token server that is used to authenticate the user. RADIUS identity stores use the UDP port for authentication sessions. The same UDP port is used for all RADIUS communication.


Note For ACS to successfully send RADIUS messages to a RADIUS-enabled server, you must ensure that the gateway devices between the RADIUS-enabled server and ACS allow communication over the UDP port. You can configure the UDP port through the ACS web interface.


This section contains the following topics:

Supported Authentication Protocols

ACS supports the following authentication protocols for RADIUS identity stores:

  • RADIUS PAP
  • TACACS+ ASCII/PAP
  • PEAP with inner EAP-GTC
  • EAP-FAST with inner EAP-GTC

Failover

ACS 5.4 allows you to configure multiple RADIUS identity stores. Each RADIUS identity store can have primary and secondary RADIUS servers. When ACS is unable to connect to the primary server, it uses the secondary server.

Password Prompt

RADIUS identity stores allow you to configure the password prompt. You can configure the password prompt through the ACS web interface.

User Group Mapping

To provide the per-user group mapping feature available in ACS 4.x, ACS 5.4 uses the attribute retrieval and authorization mechanism for users that are authenticated with a RADIUS identity store.

For this, you must configure the RADIUS identity store to return authentication responses that contain the [009\001] cisco-av-pair attribute with the following value:

ACS:CiscoSecure-Group-Id= N , where N can be any ACS group number from 0 through 499 that ACS assigns to the user.

Then, this attribute is available in the policy configuration pages of the ACS web interface while creating authorization and group mapping rules.

Groups and Attributes Mapping

You can use the RADIUS attributes retrieved during authentication against the RADIUS identity store in ACS policy conditions for authorization and group mapping. You can select the attributes that you want to use in policy conditions while configuring the RADIUS identity store. These attributes are kept in the RADIUS identity store dedicated dictionary and can be used to define policy conditions.


Note You cannot query the RADIUS server for the requested attributes. You can only configure the RADIUS identity store to return the requested attributes. These attributes are available in the Access-Accept response as part of the attributes list.


You can use the attribute subscription feature of ACS 5.4 to receive RADIUS identity store attributes can on the ACS response to the device. The following RADIUS attributes are returned:

  • Attributes that are listed in the RADIUS RFS
  • Vendor-specific attributes

The following attribute types are supported:

  • String
  • Unsigned Integer
  • IP Address
  • Enumeration

If an attribute with multiple values is returned, the value is ignored, and if a default value has been configured, that value is returned. However, this attribute is reported in the customer log as a problematic attribute.

RADIUS Identity Store in Identity Sequence

You can add the RADIUS identity store for authentication sequence in an identity sequence. However, you cannot add the RADIUS identity store for attribute retrieval sequence because you cannot query the RADIUS identity store without authentication. ACS cannot distinguish between different error cases while authenticating with a RADIUS server.

RADIUS servers return an Access-Reject message for all error cases. For example, when a user is not found in the RADIUS server, instead of returning a User Unknown status, the RADIUS server returns an Access-Reject message.

You can, however, enable the Treat Rejects as Authentication Failure or User Not Found option available in the RADIUS identity store pages of the ACS web interface.

Authentication Failure Messages

When a user is not found in the RADIUS server, the RADIUS server returns an Access-Reject message. ACS provides you the option to configure this message through the ACS web interface as either Authentication Failed or Unknown User.

However, this option returns an Unknown User message not only for cases where the user is not known, but for all failure cases.

Table 8-18 lists the different failure cases that are possible with RADIUS identity servers.

 

Table 8-18 Error Handling

Cause of Authentication Failure
Failure Cases

Authentication Failed

  • User is unknown.
  • User attempts to login with wrong passcode.
  • User logon hours expired.

Process Failed

  • RADIUS server is configured incorrectly in ACS.
  • RADIUS server is unavailable.
  • RADIUS packet is detected as malformed.
  • Problem during sending or receiving a packet from the RADIUS server.
  • Timeout.

Unknown User

Authentication failed and the 'Fail on Reject' option is set to false.

Username Special Format with Safeword Server

Safeword token server supports authentication with the following username format:

Username—Username, OTP

ACS parses the username and converts this to:

Username—Username

Safeword token servers support both the formats. ACS works with various token servers. While configuring a Safeword server, you must check the Safeword Server check box for ACS to parse the username and convert it to the specified format.

This conversion is done in the RADIUS token server identity store before the request is sent to the RADIUS token server.

User Attribute Cache

RADIUS token servers, by default, do not support user lookups. However, the user lookup functionality is essential for the following ACS features:

  • PEAP session resume—Happens after successful authentication during EAP session establishment
  • EAP/FAST fast reconnect—Happens after successful authentication during EAP session establishment
  • T+ Authorization—Happens after successful T+ Authentication

ACS caches the results of successful authentications to process user lookup requests for these features. For every successful authentication, the name of the authenticated user and the retrieved attributes are cached. Failed authentications are not written to the cache.

The cache is available in the memory at runtime and is not replicated between ACS nodes in a distributed deployment. You can configure the time to live (TTL) limit for the cache through the ACS web interface. You must enable the identity caching option and set the aging time in minutes. The cache is available in the memory for the specified amount of time.

Creating, Duplicating, and Editing RADIUS Identity Servers

ACS 5.4 supports the RADIUS identity server as an external identity store for the increased security that one-time passwords provide. RADIUS identity servers provide two-factor authentication to ensure the authenticity of the users.

To authenticate users against a RADIUS identity store, you must first create the RADIUS identity server in ACS and configure the settings for the RADIUS identity store. ACS 5.4 supports the following authentication protocols:

  • RADIUS PAP
  • TACACS+ ASCII\PAP
  • PEAP with inner EAP-GTC
  • EAP-FAST with inner EAP-GTC

For a successful authentication with a RADIUS identity server, ensure that:

  • The gateway devices between the RADIUS identity server and ACS allow communication over the UDP port.
  • The shared secret that you configure for the RADIUS identity server on the ACS web interface is identical to the shared secret configured on the RADIUS identity server.

To create, duplicate, or edit a RADIUS Identity Server:


Step 1 Choose Users and Identity Stores > External Identity Stores > RADIUS Identity Servers .

The RADIUS Identity Servers page appears with a list of RADIUS external identity servers.

Step 2 Click Create . You can also:

    • Check the check box next to the identity store you want to duplicate, then click Duplicate .
    • Click the identity store name that you want to modify, or check the box next to the name and click Edit .

Step 3 Complete the fields in the General tab. See Configuring General Settings for a description of the fields in the General tab.

Step 4 You can:

Step 5 Click Submit to save the changes.


 

Related Topics

Configuring General Settings

Table 8-19 describes the fields in the General tab of the RADIUS Identity Servers page.

 

Table 8-19 RADIUS Identity Server - General Tab

Option
Description

Name

Name of the external RADIUS identity server.

Description

(Optional) A brief description of the RADIUS identity server.

SafeWord Server

Check this check box to enable a two-factor authentication using a SafeWord server.

Server Connection

Enable Secondary Server

Check this check box to use a secondary RADIUS identity server as a backup server in case the primary RADIUS identity server fails.

If you enable the secondary server, you must configure the parameters for the secondary RADIUS identity server and must choose one of the following options:

  • Always Access Primary Server First—Select this option to ensure that ACS always accesses the primary RADIUS identity server first before the secondary server is accessed.
  • Failback To Primary Server After n Minutes—Select this option to set the number of minutes ACS can use the secondary server for authentication.

After this time expires, ACS should again attempt to authenticate using the primary server. The default value is 5 minutes.

Primary Server

Server IP Address

IP address of the primary RADIUS identity server.

Shared Secret

Shared secret between ACS and the primary RADIUS identity server.

A shared secret is an expected string of text, which a user must provide before the network device authenticates a username and password. The connection is rejected until the user supplies the shared secret.

Authentication Port

Port number on which the RADIUS primary server listens. Valid options are from 1 to 65,535. The default value is 1812.

Server Timeout n Seconds

Number of seconds, n , that ACS waits for a response from the primary RADIUS identity server before it determines that the connection to the primary server has failed. Valid options are from 1 to 300. The default value is 5.

Connection Attempts

Specifies the number of times that ACS should attempt to reconnect before contacting the secondary RADIUS identity server or dropping the connection if no secondary server is configured. Valid options are from 1 to 10. The default value is 3.

Secondary Server

Server IP Address

IP address of the secondary RADIUS identity server.

Shared Secret

Shared secret between ACS and the secondary RADIUS identity server. The shared secret must be identical to the shared secret that is configured on the RADIUS identity server.

A shared secret is an expected string of text, which a user must provide before the network device authenticates a username and password. The connection is rejected until the user supplies the shared secret.

Authentication Port

Port number on which the RADIUS secondary server listens. Valid options are from 1 to 65,535. The default value is 1812.

Server Timeout n Seconds

Number of seconds, n , that ACS waits for a response from the secondary RADIUS identity server before it determines that the connection to the secondary server has failed.

Valid options are from 1 to 300. The default value is 5.

Connection Attempts

Specifies the number of times that ACS should attempt to reconnect before dropping the request. Valid options are from 1 to 10. The default value is 3.

Related Topics

Configuring Shell Prompts

For TACACS+ ASCII authentication, ACS must return the password prompt to the user. RADIUS identity server supports this functionality by the password prompt option. ACS can use the prompt that you configure in the Shell Prompts page on the ACS web interface. If the prompt is empty, the user receives the default prompt that is configured under TACACS+ global settings.

When establishing a connection with a RADIUS identity server, the initial request packets may not have the password. You must request a password. You can use this page to define the prompt that is used to request the password. To do this:


Step 1 Enter the text for the prompt in the Prompt field.

Step 2 Do one of the following:

  • Click Submit to configure the prompt for requesting the password.
  • Click the Directory Attributes tab to define a list of attributes that you want to use in policy rule conditions. See Configuring Directory Attributes for more information.


 

Related Topics

Configuring Directory Attributes

When a RADIUS identity server responds to a request, RADIUS attributes are returned along with the response. You can make use of these RADIUS attributes in policy rules.

In the Directory Attributes tab, you can specify the RADIUS attributes that you use in policy rule conditions. ACS maintains a separate list of these attributes.


Step 1 Modify the fields in the Directory Attributes tab as described in Table 8-20 .

 

Table 8-20 RADIUS Identity Servers - Directory Attributes Tab

Option
Description

Attribute List

Use this section to create the attracted list to include in policy conditions. As you include each attribute, its name, type, default value, and policy condition name appear in the table. To:

  • Add a RADIUS attribute, fill in the fields below the table and click Add .
  • Edit a RADIUS attribute, select the appropriate row in the table and click Edit . The RADIUS attribute parameters appear in the fields below the table. Edit as required, then click Replace .

Dictionary Type

RADIUS dictionary type. Click the drop-down list box to select a RADIUS dictionary type.

RADIUS Attribute

Name of the RADIUS attribute. Click Select to choose the RADIUS attribute. This name is composed of two parts: The attribute name and an extension to support AV-pairs if the attribute selected is a Cisco AV-Pair.

For example, for an attribute, cisco-av-pair with an AV-pair name some-avpair , ACS displays cisco-av-pair.some-avpair .

IETF and vendor VSA attribute names contain an optional suffix, - nnn , where nnn is the ID of the attribute.

Type

RADIUS attribute type. Valid options are:

  • String
  • Unsigned Integer 32
  • IPv4 address

Default

(Optional) A default value that can be used if the attribute is not available in the response from the RADIUS identity server. This value must be of the specified RADIUS attribute type.

Policy Condition Name

Specify the name of the custom policy condition that uses this attribute.

Step 2 Do either of the following:

  • Click Submit to save your changes and return to the RADIUS Identity Servers page.
  • Click the Advanced tab to configure failure message handling and to enable identity caching. See Configuring Advanced Options for more information.


 

Related Topics

Configuring Advanced Options

In the Advanced tab, you can do the following:

  • Define what an access reject from a RADIUS identity server means to you.
  • Enable identity caching.

Table 8-21 describes the fields in the Advanced tab of the RADIUS Identity Servers page.

 

Table 8-21 RADIUS Identity Server - Advanced Tab

Option
Description

This Identity Store does not differentiate between 'authentication failed' and 'user not found' when an authentication attempt is rejected. From the options below, select how such an authentication reject from the Identity Store should be interpreted by ACS for Identity Policy processing and reporting.

Treat Rejects as 'authentication failed'

Click this option to consider all ambiguous access reject attempts as failed authentications.

Treat Rejects as 'user not found'

Click this option to consider all ambiguous access reject attempts as unknown users.

Identity caching is used to allow processing of requests that do not perform authentication against the server. The cache retains the results and attributes retrieved from the last successful authentication for the subject.

Enable identity caching

Check this check box to enable identity caching. If you enable identity caching, you must enter the time in minutes for which you want ACS to retain the identity cache.

Aging Time n Minutes

Enter the time in minutes for which you want ACS to retain the identity cache. Valid options are from 1 to 1440.

Click Submit to save the RADIUS Identity Server.

Related Topics

Configuring CA Certificates

When a client uses the EAP-TLS protocol to authenticate itself against the ACS server, it sends a client certificate that identifies itself to the server. To verify the identity and correctness of the client certificate, the server must have a preinstalled certificate from the Certificate Authority (CA) that has digitally signed the client certificate.

If ACS does not trust the client’s CA certificate, then you must install in ACS the entire chain of successively signed CA certificates, all the way to the top-level CA certificate that ACS trusts. CA certificates are also known as trust certificates.

You use the CA options to install digital certificates to support EAP-TLS authentication. ACS uses the X.509 v3 digital certificate standard. ACS also supports manual certificate acquisition and provides the means for managing a certificate trust list (CTL) and certificate revocation lists (CRLs).

Digital certificates do not require the sharing of secrets or stored database credentials. They can be scaled and trusted over large deployments. If managed properly, they can serve as a method of authentication that is stronger and more secure than shared secret systems.

Mutual trust requires that ACS have an installed certificate that can be verified by end-user clients. This server certificate may be issued from a CA or, if you choose, may be a self-signed certificate. For more information, see Configuring Local Server Certificates.


Note ACS builds a certificate chain with the CA certificates that you add to it and uses this chain during TLS negotiations. You must add the certificate that signed the server certificate to the CA. You must ensure that the chain is signed correctly and that all the certificates are valid.


If the server certificate and the CA that signed the server certificate are installed on ACS, ACS sends the full certificate chain to the client.

Related Topics

Adding a Certificate Authority

The supported certificate formats are DER, PEM, or CER.

To add a trusted CA (Certificate Authority) certificate:


Step 1 Select Users and Identity Stores > Certificate Authorities .

The Trust Certificate page appears.

Step 2 Click Add .

Step 3 Complete the fields in the Certificate File to Import page as described in Table 8-22 :

 

Table 8-22 Certificate Authority Properties Page

Option
Description
Certificate File to Import

Certificate File

Enter the name of the certificate file. Click Browse to navigate to the location on the client machine where the trust certificate is located.

Trust for client with EAP-TLS

Check this box so that ACS will use the certificate trust list for the EAP protocol.

Allow Duplicate Certificates

Allows you to add certificates with the same CN and SKI with different Valid From, Valid To, and Serial numbers.

Description

Enter a description of the CA certificate.

Step 4 Click Submit .

The new certificate is saved. The Trust Certificate List page appears with the new certificate.


 

Related Topics

Editing a Certificate Authority and Configuring Certificate Revocation Lists

Use this page to edit a trusted CA (Certificate Authority) certificate.


Step 1 Select Users and Identity Stores > Certificate Authorities.

The Trust Certificate page appears with a list of configured certificates.

Step 2 Click the name that you want to modify, or check the check box for the Name, and click Edit .

Complete the fields in the Edit Trust Certificate List Properties Page as described in Table 8-23 :

When ACS delays the CA CRL, CA is retained on the local file system. The CA is not refreshed until you resubmit it.

By default ACS will fail all user certificates of a CA for which the CRL has expired.

    • If CA is resubmitted, the following error is shown: 12514 EAP-TLS failed SSL/TLS handshake. This is because of the unknown CA.
    • If CA is not resubmitted, the following error is shown: 12515 EAP-TLS failed SSL/TLS handshake. This is because of the expired CRL.

If you choose Ignore CRL Expiration, authentication will fail for revoked certificates and successful for non-revoked certificates.

 

Table 8-23 Edit Certificate Authority Properties Page

Option
Description
Issuer

Friendly Name

The name that is associated with the certificate.

Description

(Optional) A brief description of the CA certificate.

Issued To

Display only . The entity to which the certificate is issued. The name that appears is from the certificate subject.

Issued By

Display only. The certification authority that issued the certificate.

Valid from

Display only. The start date of the certificate’s validity. An X509 certificate is valid only from the start date to the end date (inclusive).

Valid To (Expiration)

Display only. The last date of the certificate’s validity.

Serial Number

Display only. The serial number of the certificate.

Description

Description of the certificate.

Usage

Trust for client with EAP-TLS

Check this box so that ACS will use the trust list for the TLS related EAP protocols.

Certificate Status Validation

 

OCSP Configuration

Use this section to configure the OCSP service.

Validate against OCSP service

Check this box and select the OCSP service from the drop-down list to validate the requests against the selected the OCSP service.

Reject the request if certificate status could not be determined by OCSP

Check this box to reject the request if the certificate status could not be determined by the OCSP service.

Certificate Revocation List Configuration

Use this section to configure the CRL.

Download CRL

Check this box to download the CRL.

CRL Distribution URL

Enter the CRL distribution URL. You can specify a URL that uses HTTP.

Retrieve CRL

ACS attempts to download a CRL from the CA. Toggle the time settings for ACS to retrieve a new CRL from the CA.

  • Automatically —Obtain the next update time from the CRL file. If unsuccessful, ACS tries to retrieve the CRL periodically after the first failure until it succeeds.
  • Every—Determines the frequency between retrieval attempts. Enter the amount in units of time.

If Download Failed Wait

Enter the amount of time to attempt to retrieve the CRL, if the retrieval initially failed.

Bypass CRL Verification if CRL is not Received

If unchecked, all the client requests that use the certificate that is signed by the selected CA will be rejected until ACS receives the CRL file. When checked, the client request may be accepted before the CRL is received.

Ignore CRL Expiration

Check this box to check a certificate against an outdated CRL.

  • When checked, ACS continues to use the expired CRL and permits or rejects EAP-TLS authentications according to the contents of the CRL.
  • When unchecked, ACS examines the expiration date of the CRL in the Next Update field in the CRL file. If the CRL has expired, all authentications that use the certificate that is signed by the selected CA are rejected.

Step 3 Click Submit .

The Trust Certificate page appears with the edited certificate.


 

The administrator has the rights to configure CRL and OCSP verification. If both CRL and OCSP verification are configured at the same time, then ACS performs OCSP verification first. If it detects any communication problems with either the primary or secondary servers, or if the verification returns the status of a given certificate as unknown, then ACS moves on to perform the CRL validation.

Related Topics

Deleting a Certificate Authority

Use this page to delete a trusted CA (Certificate Authority) certificate:


Step 1 Select Users and Identity Stores > Certificate Authorities .

The Trust Certificate List page appears with a list of configured certificates.

Step 2 Check one or more check boxes next to the certificates that you want to delete.

Step 3 Click Delete .

Step 4 Click Yes to confirm.

The Trust Certificate page appears without the deleted certificate(s).


 

Related Topic

Exporting a Certificate Authority

To export a trust certificate:


Step 1 Select Users and Identity Stores > Certificate Authorities .

The Trust Certificate List page appears with a list of configured certificates.

Step 2 Check the box next to the certificates that you want to export.

Step 3 Click Export .

This operation exports the trusted certificate to the client machine.

Step 4 Click Yes to confirm.

You are prompted to install the exported certificate on your client machine.


 

Related Topics

Configuring Certificate Authentication Profiles

The certificate authentication profile defines the X509 certificate information to be used for a certificate- based access request. You can select an attribute from the certificate to be used as the username.

You can select a subset of the certificate attributes to populate the username field for the context of the request. The username is then used to identify the user for the remainder of the request, including the identification used in the logs.

You can use the certificate authentication profile to retrieve certificate data to further validate a certificate presented by an LDAP or AD client. The username from the certificate authentication profile is used to query the LDAP or AD identity store.

ACS compares the client certificate against all certificates retrieved from the LDAP or AD identity store, one after another, to see if one of them matches. ACS either accepts or rejects the request.


Note For ACS to accept a request, only one certificate from either the LDAP or the AD identity store must match the client certificate.


When ACS processes a certificate-based request for authentication, one of two things happens: the username from the certificate is compared to the username in ACS that is processing the request, or ACS uses the information that is defined in the selected LDAP or AD identity store to validate the certificate information.

You can duplicate a certificate authentication profile to create a new profile that is the same, or similar to, an existing certificate authentication profile. After duplication is complete, you access each profile (original and duplicated) separately, to edit or delete them.

ACS 5.4 now supports certificate name constraint extension. It accepts the client certificates whose issuers contain the name constraint extension. It checks the client certificates for CA and sub-CA certificates. This extension defines a name space for all subject names in the subsequent certificates in a certificate path. It applies to both the subject distinguished name and the subject alternative name. These restrictions are applicable only when the specified name form is present in the client certificate. The ACS authentication fails if the client certificate is excluded or not permitted by the namespace.

Supported Name Constraints:

  • Directory name
  • DNS
  • Email
  • URL

Unsupported Name Constraints:

  • IP address
  • Other name

To create, duplicate, or edit a certificate authentication profile, complete the following steps:


Step 1 Select Users and Identity Stores > Certificate Authentication Profile .

The Certificate Authentication Profile page appears.

Step 2 Do one of the following:

    • Click Create .
    • Check the check box next to the certificate authentication profile that you want to duplicate, then click Duplicate .
    • Click the certificate authentication profile that you want to modify, or check the check box next to the name and click Edit .

The Certificate Authentication Profile Properties page appears.

Step 3 Complete the fields in the Certificate Authentication Profile Properties page as described in Table 8-24 :

 

Table 8-24 Certificate Authentication Profile Properties Page

Option
Description
General

Name

Enter the name of the certificate authentication profile.

Description

Enter a description of the certificate authentication profile.

Certificate Definition

Principal Username X509 Attribute

Available set of principal username attributes for x509 authentication. The selection includes:

  • Common Name
  • Subject Alternative Name
  • Subject Serial Number
  • Subject
  • Subject Alternative Name - Other Name
  • Subject Alternative Name - EMail
  • Subject Alternative Name - DNS

Perform Binary Certificate Comparison with Certificate retrieved from LDAP or Active Directory

Check this check box if you want to validate certificate information for authentication against a selected LDAP or AD identity store.

If you select this option, you must enter the name of the LDAP or AD identity store, or click Select to select the LDAP or AD identity store from the available list.

Step 4 Click Submit.

The Certificate Authentication Profile page reappears.


 

Related Topics

Configuring Identity Store Sequences

An access service identity policy determines the identity sources that ACS uses for authentication and attribute retrieval. An identity source consists of a single identity store or multiple identity methods. When you use multiple identity methods, you must first define them in an identity store sequence, and then specify the identity store sequence in the identity policy.

An identity store sequence defines the sequence that is used for authentication and attribute retrieval and an optional additional sequence to retrieve additional attributes.

Authentication Sequence

An identity store sequence can contain a definition for certificate-based authentication or password-based authentication or both.

  • If you select to perform authentication based on a certificate, you specify a single Certificate Authentication Profile, which you have already defined in ACS.
  • If you select to perform authentication based on a password, you can define a list of databases to be accessed in sequence.

When authentication succeeds, any defined attributes within the database are retrieved. You must have defined the databases in ACS.

Attribute Retrieval Sequence

You can optionally define a list of databases from which to retrieve additional attributes. These databases can be accessed regardless of whether you use password or certificate-based authentication. When you use certificate-based authentication, ACS populates the username field from a certificate attribute and then uses the username to retrieve attributes.

ACS can retrieve attributes for a user, even when:

  • The user’s password is flagged for a mandatory change.
  • The user’s account is disabled.

When you perform password-based authentication, you can define the same identity database in the authentication list and the attribute retrieval list. However, if the database is used for authentication, it will not be accessed again as part of the attribute retrieval flow.

ACS authenticates a user or host in an identity store only when there is a single match for that user or host. If an external database contains multiple instances of the same user, authentication fails. Similarly, ACS retrieves attributes only when a single match for the user or host exists; otherwise, ACS skips attribute retrieval from that database.

This section contains the following topics:

Creating, Duplicating, and Editing Identity Store Sequences

To create, duplicate, or edit an identity store sequence:


Step 1 Select Users and Identity Stores > Identity Store Sequences .

The Identity Store Sequences page appears.

Step 2 Do one of the following:

    • Click Create .
    • Check the check box next to the sequence that you want to duplicate, then click Duplicate .
    • Click the sequence name that you want to modify, or check the check box next to the name and click Edit .

The Identity Store Sequence Properties page appears as described in Table 8-25 .

 

Table 8-25 Identity Store Sequence Properties Page

Option
Description
General

Name

Enter the name of the identity store sequence.

Description

Enter a description of the identity store sequence.

Authentication Method List

Certificate Based

Check this check box to use the certificate-based authentication method. If you choose this option, you must enter the certificate authentication profile. Click Select to choose the profile from a list of available profiles.

Password Based

Check this check box to use the password-based authentication method. If you choose this option, you must choose the set of identity stores that ACS will access one after another until a match is found.

If you choose this option, you must select a list of identity stores in the Authentication and Attribute Retrieval Search List area for ACS to access the identity stores one after another.

Authentication and Attribute Retrieval Search List

Note This section appears only when you check the Password Based option.

Available

Available set of identity stores to access.

Selected

Selected set of identity stores to access in sequence until first authentication succeeds. Use the Up and Down arrows at the right of the list to define the order of access.

ACS automatically retrieves attributes from identity stores that you selected for authentication. You do not need to select the same identity stores for attribute retrieval.

Additional Attribute Retrieval Search List

Available

Available set of additional identity stores for attribute retrieval.

Selected

(Optional) The selected set of additional identity stores for attribute retrieval. Use the Up and Down arrows at the right of the list to define the order of access.

ACS automatically retrieves attributes from identity stores that you selected for authentication. You do not need to select the same identity stores for attribute retrieval.

Internal User/Host

If internal user/host is not found or disabled then exit the sequence and treat as User Not Found

This option is applicable for the attribute phase and when the Internal Identity Store is in the Attribute retrieval list.

ACS exists the sequence and treats it as User Not Found if this option is selected and the user not found or is disabled.

Advanced Options

Break sequence

If this option is selected and if an authentication attempt against current Identity Store results in process error, the flow breaks the Identity Stores sequence. The flow then continues to the Fail-Open option configured in the Identity Policy.

The same applies to attribute retrieval.

Continue to next identity store in the sequence

If this is checked and if authentication with the current Identity Store results in a process error, the flow tries to authenticate it with the next Identity Store in the authentication list.

The same applies to attribute retrieval phase.

Step 3 Click Submit .

The Identity Store Sequences page reappears.


 

Related Topics

Deleting Identity Store Sequences

To delete an identity store sequence:


Step 1 Select Users and Identity Stores > Identity Store Sequences .

The Identity Store Sequences page appears with a list of your configured identity store sequences.

Step 2 Check one or more check boxes next to the identity store sequences that you want to delete.

Step 3 Click Delete .

The following error message appears:

Are you sure you want to delete the selected item/items?

Step 4 Click OK .

The Identity Store Sequences page appears, without the deleted identity store sequence(s) listed.


 

Related Topics