Cisco Security Appliance Configuration Guide using ASDM, 6.2
Configuring Dynamic Access Policies
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Configuring Dynamic Access Policies

Table Of Contents

Configuring Dynamic Access Policies

Understanding VPN Access Policies

DAP Support for Remote Access Connection Types

DAP and AAA

DAP and Endpoint Security

DAP Connection Sequence

Test Dynamic Access Policies

Add/Edit Dynamic Access Policies

Add/Edit AAA Attributes

Retrieving Active Directory Groups

Add/Edit Endpoint Attributes

Guide

Syntax for Creating Lua EVAL Expressions

The DAP CheckAndMsg Function

Additional Lua Functions

CheckAndMsg with Custom Function Example

Further Information on Lua

Operator for Endpoint Category

DAP Examples


Configuring Dynamic Access Policies


This chapter describes how to configure dynamic access policies. It includes the following sections.

Understanding VPN Access Policies

Add/Edit Dynamic Access Policies

Add/Edit AAA Attributes

Retrieving Active Directory Groups

Add/Edit Endpoint Attributes

Operator for Endpoint Category

DAP Examples

Understanding VPN Access Policies

VPN gateways operate in dynamic environments. Multiple variables can affect each VPN connection, for example, intranet configurations that frequently change, the various roles each user may inhabit within an organization, and logins from remote access sites with different configurations and levels of security. The task of authorizing users is much more complicated in a VPN environment than it is in a network with a static configuration.

Dynamic access policies (DAP) on the security appliance let you configure authorization that addresses these many variables. You create a dynamic access policy by setting a collection of access control attributes that you associate with a specific user tunnel or session. These attributes address issues of multiple group membership and endpoint security. That is, the security appliance grants access to a particular user for a particular session based on the policies you define. It generates a DAP at the time the user connects by selecting and/or aggregating attributes from one or more DAP records. It selects these DAP records based on the endpoint security information of the remote device and the AAA authorization information for the authenticated user. It then applies the DAP record to the user tunnel or session.

The DAP system includes the following components that require your attention:

DAP Selection Configuration File—A text file containing criteria that the security appliance uses for selecting and applying DAP records during session establishment. Stored on the security appliance. You can use ASDM to modify it and upload it to the security appliance in XML data format. DAP selection configuration files include all of the attributes that you configure. These can include AAA attributes, endpoint attributes, and access policies as configured in network and web-type ACL filter, port forwarding and URL lists,

DfltAccess Policy—Always the last entry in the DAP summary table, always with a priority of 0. You can configure Access Policy attributes for the default access policy, but it does not contain—and you cannot configure—AAA or endpoint attributes. You cannot delete the DfltAccessPolicy, and it must be the last entry in the summary table.

For more information about Dynamic Access Policies, see the following sections.

DAP Support for Remote Access Connection Types

DAP and AAA

DAP and Endpoint Security

DAP Connection Sequence

Test Dynamic Access Policies

DAP Examples

You can also refer to the Dynamic Access Deployment Guide (http://supportwiki.cisco.com/ViewWiki/index.php/ASA_8.x_Dynamic_Access_Policies_%28DAP%29_Deployment_Guide) for more information.

Configuring Dynamic Access Policies

Figure 37-1shows the Dynamic Access Policies pane.

Figure 37-1 Dynamic Access Policies ASDM pane

To configure dynamic access policies, in the Configuration > Remote Access VPN > Network (Client) Access or Clientless SSL VPN Access > Dynamic Access Policies pane in ASDM, perform the following steps:


Step 1 To include certain antivirus, antispyware, or personal firewall endpoint attributes, click the CSD configuration link near the top of the pane. Then enable Cisco Secure Desktop and Host Scan extensions. This link does not display if you have previously enabled both of these features.

If you enable Cisco Secure Desktop, but do not enable Host Scan extensions, when you apply your changes ASDM includes a link to enable Host Scan configuration.

Step 2 To create a new dynamic access policy, click Add. To modify an existing policy, click Edit.

Step 3 To test already configured polices, click Test Dynamic Access Policies.


Fields

Priority—Displays the priority of the DAP record. The security appliance uses this value to logically sequence the access lists when aggregating the network and web-type ACLs from multiple DAP records. The security appliance orders the records from highest to lowest priority number, with lowest at the bottom of the table. Higher numbers have a higher priority, that is a DAP record with a value of 4 has a higher priority than a record with a value of 2. You cannot manually sort them.

Name—Displays the name of the DAP record.

Network ACL List—Displays the name of the firewall access list that applies to the session.

Web-Type ACL List—Displays the name of the SSL VPN access list that applies to the session.

Description—Describes the purpose of the DAP record.

Test Dynamic Access Policies button—Click to test already configured DAP records.

Modes

The following table shows the modes in which this feature is available:

Firewall Mode
Security Context
Routed
Transparent
Single
Multiple
Context
System


DAP Support for Remote Access Connection Types

The DAP system supports the following remote access methods:

IPsec VPN

Clientless (browser-based) SSLVPN

Cisco AnyConnect SSL VPN

PIX cut-through proxy (posture assessment not available)

DAP and AAA

DAP complements AAA services. It provides a limited set of authorization attributes that can override those AAA provides. The security appliance selects DAP records based on the AAA authorization information for the user and posture assessment information for the session. The security appliance can select multiple DAP records depending on this information, which it then aggregates to create DAP authorization attributes.

You can specify AAA attributes from the Cisco AAA attribute hierarchy, or from the full set of response attributes that the security appliance receives from a RADIUS or LDAP server. For more information about DAP and AAA, see the section, Add/Edit AAA Attributes.

AAA Attribute Definitions

Table 37-1 defines the AAA selection attribute names that are available for DAP use. The Attribute Name field shows you how to enter each attribute name in a Lua logical expression, which you might do in the Advanced section of the Add/Edit Dynamic Access Policy pane.

Table 37-1 AAA Selection Attributes for DAP Use 

Attribute Type
Attribute Name
Source
Value
Max String Length
Description

Cisco

aaa.cisco.grouppolicy

AAA

string

64

Group policy name on the security appliance or sent from a Radius/LDAP server as the IETF-CLass (25) attribute

 

aaa.cisco.ipaddress

AAA

number

-

Assigned IP address for full tunnel VPN clients (IPsec, L2TP/IPsec, SSL VPN AnyConnect)

 

aaa.cisco.tunnelgroup

AAA

string

64

Connection profile (tunnel group) name

 

aaa.cisco.username

AAA

string

64

Name of the authenticated user (applies if using Local authentication/authorization)

LDAP

aaa.ldap.<label>

LDAP

string

128

LDAP attribute value pair

RADIUS

aaa.radius.<number>

RADIUS

string

128

Radius attribute value pair

See Security Appliance Supported RADIUS Attributes and Values for a table that lists RADIUS attributes that the security appliance supports.


DAP and Endpoint Security

The security appliance obtains endpoint security attributes by using posture assessment methods that you configure. These include Cisco Secure Desktop and NAC. For details, see the Cisco Secure Desktop section of ASDM. Table 37-2 identifies each of the remote access protocols DAP supports, the posture assessment tools available for that method, and the information that tool provides.

Table 37-2 DAP Posture Assessment 

Remote Access Protocol
Cisco Secure Desktop
Host Scan
NAC
Cisco NAC Appliance
 

Returns files information, registry key values, running processes, operating system

Returns antivirus, antispyware, and personal firewall software information

Returns NAC status

Returns VLAN Type and VLAN IDs

IPsec VPN

1

X

X

Cisco AnyConnect VPN

X

X

X

X

Clientless VPN

X

X

PIX Cut-through Proxy

1 — indicates no; X indicates yes.


Endpoint Attribute Definitions

Table 37-3 defines the endpoint selection attribute names that are available for DAP use.The Attribute Name field shows you how to enter each attribute name in a Lua logical expression, which you might do in the Advanced area in the Add/Edit Dynamic Access Policy pane. The label variable identifies the application, filename, process, or registry entry.

Table 37-3 Endpoint Attribute Definitions 

Attribute Type
Attribute Name
Source
Value
Max String Length
Description

Antispyware (Requires Cisco Secure Desktop)

endpoint.as["label"].exists

Host Scan

true

Antispyware program exists

endpoint.as["label"].version

string

32

Version

endpoint.as["label"].description

string

128

Antispyware description

endpoint.as["label"].lastupdate

integer

Seconds since update of antispyware definitions

Antivirus

(Requires Cisco Secure Desktop)

endpoint.av["label"].exists

Host Scan

true

Antivirus program exists

endpoint.av["label"].version

string

32

Version

endpoint.av["label"].description

string

128

Antivirus description

endpoint.av["label"].lastupdate

integer

Seconds since update of antivirus definitions

AnyConnect

(Does not require Cisco Secure Desktop or Host Scan.)

endpoint.anyconnect.clientversion

Endpoint

version

AnyConnect client version.

endpoint.anyconnect.platform

string

Operating system on which AnyConnect client is installed.

endpoint.anyconnect.platformversion

version

64

Version of operating system on which AnyConnect client is installed.

endpoint.anyconnect.devicetype

string

64

Mobile device type on which AnyConnect client is installed.

endpoint.anyconnect.deviceuniqueid

caseless

64

Unique ID of mobile device on which AnyConnect client is installed.

Application

endpoint.application.clienttype

Application

string

Client type:

CLIENTLESS

ANYCONNECT

IPSEC

L2TP

File

endpoint.file["label"].exists

Secure Desktop

true

The files exists

endpoint.file["label"].lastmodified

integer

Seconds since file was last modified

endpoint.file["label"].crc.32

integer

CRC32 hash of the file

NAC

endpoint.nac.status

NAC

string

User defined status string

Operating System

endpoint.os.version

Secure Desktop

string

32

Operating system

endpoint.os.servicepack

integer

Service pack for Windows

Personal firewall

(Requires Secure Desktop)

endpoint.fw["label"].exists

Host Scan

true

The personal firewall exists

endpoint.fw["label"].version

string

32

Version

endpoint.fw["label"].description

string

128

Personal firewall description

Policy

endpoint.policy.location

Secure Desktop

string

64

Location value from Cisco Secure Desktop

Process

endpoint.process["label"].exists

Secure Desktop

true

The process exists

endpoint.process["label"].path

string

255

Full path of the process

Registry

endpoint.registry["label"].type

Secure Desktop

dword
string

dword

endpoint.registry["label"].value

string

255

Value of the registry entry

VLAN

endoint.vlan.type

CNA

string

VLAN type:

ACCESS
AUTH
ERROR
GUEST
QUARANTINE
ERROR
STATIC
TIMEOUT


DAP and AntiVirus, AntiSpyware, and Personal Firewall Programs

The security appliance uses a DAP policy when the user attributes matches the configured AAA and endpoint attributes. The Prelogin Assessment and Host Scan modules of Cisco Secure Desktop return information to the security appliance about the configured endpoint attributes, and the DAP subsystem uses that information to select a DAP record that matches the values of those attributes.

Most, but not all, antivirus, antispyware, and personal firewall programs support active scan, which means that the programs are memory-resident, and therefore always running. Host Scan checks to see if an endpoint has a program installed, and if it is memory-resident as follows:

If the installed program does not support active scan, Host Scan reports the presence of the software. The DAP system selects DAP records that specify the program.

If the installed program does support active scan, and active scan is enabled for the program, Host Scan reports the presence of the software. Again the security appliance selects DAP records that specify the program.

If the installed program does support active scan and active scan is disabled for the program, Host Scan ignores the presence of the software. The security appliance does not select DAP records that specify the program. Further, the output of the debug trace command, which includes a lot of information about DAP, does not indicate the program presence, even though it is installed.

DAP Connection Sequence

The following sequence outlines a typical remote access connection establishment.

1. A remote client attempts a VPN connection.

2. The security appliance performs posture assessment, using configured NAC and Cisco Secure Desktop Host Scan values.

3. The security appliance authenticates the user via AAA. The AAA server also returns authorization attributes for the user.

4. The security appliance applies AAA authorization attributes to the session, and establishes the VPN tunnel.

5. The security appliance selects DAP records based on the user AAA authorization information and the session posture assessment information.

6. The security appliance aggregates DAP attributes from the selected DAP records, and they become the DAP policy.

7. The security appliance applies the DAP policy to the session.

Test Dynamic Access Policies

Figure 37-2 shows the Test Dynamic Access Policies pane.

Figure 37-2 Test Dynamic Access Policies Pane

This pane lets you test the retrieval of the set of DAP records configured on the device by specifying authorization attribute value pairs. To specify these pairs, use the Add/Edit buttons associated with the AAA Attribute and Endpoint Attribute tables. The dialogs that display when you click these Add/Edit buttons are similar to those in the Add/Edit AAA Attributes and Add/Edit Endpoint Attributes dialog boxes.

When you enter attribute value pairs and click the "Test" button, the DAP subsystem on the device references these values when evaluating the AAA and endpoint selection attributes for each record. The results display in the "Test Results" text area.

Fields

Selection Criteria—Determine the AAA and endpoint attributes to test for dynamic access policy retrieval.

AAA Attributes

AAA Attribute—Identifies the AAA attribute.

Operation Value—Identifies the attribute as =/!= to the given value.

Add/Edit—Click to add or edit a AAA attribute.

Endpoint Attributes—Identifies the endpoint attribute.

Endpoint ID—Provides the endpoint attribute ID.

Name/Operation/Value—

Add/Edit/Delete—Click to add, edit or delete and endpoint attribute.

Test Result—Displays the result of the test.

Test—Click to test the retrieval of the policies you have set.

Close—Click to close the pane.

Modes

The following table shows the modes in which this feature is available:

Firewall Mode
Security Context
Routed
Transparent
Single
Multiple
Context
System


Add/Edit Dynamic Access Policies

Figure 37-3Clicking Add or Edit shows the Add/Edit Dynamic Access Policies pane.

Figure 37-3 Add/Edit Dynamic Access Policies Pane

To add or edit a dynamic access policy, perform the following steps:


Step 1 At the top of the Add/Edit Dynamic Access Policy pane, provide a name (required) and a description (optional) of this dynamic access policy.

Step 2 In the ACL Priority field, set a priority for the dynamic access policy. The ACL Priority is used for the aggregation of ACLs and their sequence ordering, when multiple ACLs and/or DAP records are matched.

Step 3 In the Add/Edit AAA Attributes field, use the ANY/ALL/NONE drop-down list (unlabeled) to choose whether a user must have any, all, or none of the AAA attribute values you configure to use this dynamic access policy.

Step 4 To Set AAA attributes, click Add/Edit in the AAA Attributes field.

Step 5 Before you set endpoint attributes, configure CSD Host Scan.

Step 6 To set endpoint security attributes, click Add/Edit in the Endpoint ID field.

Step 7 You can create multiple instances of each type of endpoint attribute. For each of these types, you need to decide whether the DAP policy should require that the user have all instances of a type (Match all = AND) or only one of them (Match Any = OR). To set this value for each of the end point attributes, click the Logical Op. button.

Step 8 In the Advanced field you can enter one or more logical expressions to set AAA or endpoint attributes other than what is possible in the AAA and Endpoint areas above.

Step 9 To configure network and webtype ACLs, file browsing, file server entry, HTTP proxy, URL entry, port forwarding lists and URL lists, set values in the Access Policy Attributes fields.


Fields

Policy Name—A string of 4 through 32 characters, no spaces allowed.

Description—(Optional) Describes the purpose of the DAP record. Maximum 80 characters.

Priority—Sets the priority of the DAP. The security appliance applies access policies in the order you set here, highest number having the highest priority. Values of 0 to 2147483647 are valid. Default = 0.

ANY/ALL/NONE drop-down list—Set to require that user authorization attributes match any, all, or none of the values in the AAA attributes you are configuring, as well as satisfying every endpoint attribute. Duplicate entries are not allowed. If you configure a DAP record with no AAA or endpoint attributes, the security appliance always selects it since all selection criteria are satisfied.

AAA Attributes—Displays the configured AAA attributes.

Attribute—Displays the name of the AAA attribute.

Operation/Value—=/!=

Add/Edit/Delete—Click to add, edit, or delete the highlighted AAA attribute.

Endpoint Attributes—Displays the configured endpoint attributes

Endpoint ID—Identifies endpoint attributes.

Name/Operation/Value—Summarizes configured values for each endpoint attribute.

Add/Edit/Delete—Click to add, edit, or delete the highlighted endpoint attribute.


Note Cisco Secure Desktop provides the security appliance with all endpoint attributes except Application and NAC. To configure all other endpoint attributes, you must first enable Cisco Secure Desktop, and configure the relevant endpoint attributes there as well.


Logical Op.—You can create multiple instances of each type of endpoint attribute. Click to configure whether the DAP policy should require that the user have all instances of a type (Match all = AND) or only one of them (Match Any = OR). Be aware that for some endpoint attributes, for example OS, it can never happen that a user would have more than one instance of the attribute.

Advanced—Click to set additional attributes for the dynamic access policy. Be aware that this is an advanced feature that requires knowledge of Lua.

AND/OR—Click to define the relationship between the basic selection rules and the logical expressions you enter here, that is, whether the new attributes add to or substitute for the AAA and endpoint attributes already set. The default is AND.

Logical Expressions—You can configure multiple instances of each type of endpoint attribute. Enter free-form Lua text that defines new AAA and/or endpoint selection attributes. ASDM does not validate text that you enter here; it just copies this text to the DAP XML file, and the security appliance processes it, discarding any expressions it cannot parse.

Guide—Click to display online help for creating these logical operations.

Access Policy Attributes—These tabs let you set attributes for network and webtype ACL filters, file access, HTTP proxy, URL entry and lists, port forwarding, and clientless SSL VPN access methods. Attribute values that you configure here override authorization values in the AAA system, including those in existing user, group, tunnel group, and default group records.

Action Tab

Action—Specifies special processing to apply to a specific connection or session.

Continue—(Default) Click to apply access policy attributes to the session.

Terminate—Click to terminate the session.

User Message—Enter a text message to display on the portal page when this DAP record is selected. Maximum 128 characters. A user message displays as a yellow orb. When a user logs on it blinks three times to attract attention, and then it is still. If several DAP records are selected, and each of them has a user message, all of the user messages display.


Note You can include in such messages URLs or other embedded text, which require that you use the correct HTML tags.

For example: All contractors please read <a href='http://wwwin.abc.com/procedure.html'> Instructions</a> for the procedure to upgrade your antivirus software.


Network ACL Filters Tab—Lets you select and configure network ACLs to apply to this DAP record. An ACL for DAP can contain permit or deny rules, but not both. If an ACL contains both permit and deny rules, the security appliance rejects it.

Network ACL drop-down list—Select already configured network ACLs to add to this DAP record. Only ACLs having all permit or all deny rules are eligible, and these are the only ACLs that display here.

Manage...—Click to add, edit, and delete network ACLs.

Network ACL list—Displays the network ACLs for this DAP record.

Add—Click to add the selected network ACL from the drop-down list to the Network ACLs list on the right.

Delete—Click to delete a highlighted network ACL from the Network ACLs list. You cannot delete an ACL from the security appliance unless you first delete it from DAP records.

Web-Type ACL Filters Tab—Lets you select and configure web-type ACLs to apply to this DAP record. An ACL for DAP can contain only permit or deny rules. If an ACL contains both permit and deny rules, the security appliance rejects it.

Web-Type ACL drop-down list—Select already configured web-type ACLs to add to this DAP record. Only ACLs having all permit or all deny rules are eligible, and these are the only ACLs that display here.

Manage...—Click to add, edit, and delete web-type ACLs.

Web-Type ACL list—Displays the web-type ACLs for this DAP record.

Add—Click to add the selected web-type ACL from the drop-down list to the Web-Type ACLs list on the right.

Delete—Click to delete a web-type ACL from the Web-Type ACLs list. You cannot delete an ACL from the security appliance unless you first delete it from DAP records.

Functions Tab—Lets you configure file server entry and browsing, HTTP proxy, and URL entry for the DAP record.

File Server Browsing—Enables or disables CIFS browsing for file servers or shared features.


Note Browsing requires NBNS (Master Browser or WINS). If that fails or is not configured, we use DNS.

The CIFS browse feature does not support internationalization.


File Server Entry—Lets or prohibits a user from entering file server paths and names on the portal page. When enabled, places the file server entry drawer on the portal page. Users can enter pathnames to Windows files directly. They can download, edit, delete, rename, and move files. They can also add files and folders. Shares must also be configured for user access on the applicable Windows servers. Users might have to be authenticated before accessing files, depending on network requirements.

HTTP Proxy—Affects the forwarding of an HTTP applet proxy to the client. The proxy is useful for technologies that interfere with proper content transformation, such as Java, ActiveX, and Flash. It bypasses mangling while ensuring the continued use of the security appliance. The forwarded proxy modifies the browser's old proxy configuration automatically and redirects all HTTP and HTTPS requests to the new proxy configuration. It supports virtually all client side technologies, including HTML, CSS, JavaScript, VBScript, ActiveX, and Java. The only browser it supports is Microsoft Internet Explorer.

URL Entry—Allows or prevents a user from entering HTTP/HTTPS URLs on the portal page. If this feature is enabled, users can enter web addresses in the URL entry box, and use clientless SSL VPN to access those websites.

Using SSL VPN does not ensure that communication with every site is secure. SSL VPN ensures the security of data transmission between the remote user PC or workstation and the security appliance on the corporate network. If a user then accesses a non-HTTPS web resource (located on the Internet or on the internal network), the communication from the corporate security appliance to the destination web server is not secured.

In a clientless VPN connection, the security appliance acts as a proxy between the end user web browser and target web servers. When a user connects to an SSL-enabled web server, the security appliance establishes a secure connection and validates the server SSL certificate. The end user browser never receives the presented certificate, so therefore cannot examine and validate the certificate. The current implementation of SSL VPN does not permit communication with sites that present expired certificates. Neither does the security appliance perform trusted CA certificate validation. Therefore, users cannot analyze the certificate an SSL-enabled web-server presents before communicating with it.

To limit Internet access for users, choose Disable for the URL Entry field. This prevents SSL VPN users from surfing the web during a clientless VPN connection.

Unchanged—(default) Click to use values from the group policy that applies to this session.

Enable/Disable—Click to enable or disable the feature.

Auto-start—Click to enable HTTP proxy and to have the DAP record automatically start the applets associated with these features.

Port Forwarding Lists Tab—Lets you select and configure port forwarding lists for user sessions.

Port Forwarding provides access for remote users in the group to client/server applications that communicate over known, fixed TCP/IP ports. Remote users can use client applications that are installed on their local PC and securely access a remote server that supports that application. Cisco has tested the following applications: Windows Terminal Services, Telnet, Secure FTP (FTP over SSH), Perforce, Outlook Express, and Lotus Notes. Other TCP-based applications may also work, but Cisco has not tested them.


Note Port Forwarding does not work with some SSL/TLS versions.



Caution Make sure Sun Microsystems Java Runtime Environment (JRE) 1.4+ is installed on the remote computers to support port forwarding (application access) and digital certificates.

Port Forwarding—Select an option for the port forwarding lists that apply to this DAP record. The other attributes in this field are enabled only when you set Port Forwarding to Enable or Auto-start.

Unchanged—Click to remove the attributes from the running configuration.

Enable/Disable—Click to enable or disable port forwarding.

Auto-start—Click to enable port forwarding, and to have the DAP record automatically start the port forwarding applets associated with its port forwarding lists.

Port Forwarding List drop-down list—Select already configured port forwarding lists to add to the DAP record.

New...—Click to configure new port forwarding lists.

Port Forwarding Lists (unlabeled)—Displays the port forwarding lists for the DAP record.

Add—Click to add the selected port forwarding list from the drop-down list to the Port Forwarding list on the right.

Delete—Click to delete selected port forwarding list from the Port Forwarding list. You cannot delete a port forwarding list from the security appliance unless you first delete it from DAP records.

URL Lists Tab—Lets you select and configure URL lists for user sessions.

Enable URL Lists—Click to enable. When unchecked, no URL lists display in the portal page for the connection.

URL List drop-down list—select already configured URL lists to add to the DAP record.

Manage...—Click to add, import, export, and delete URL lists.

URL Lists (unlabeled)—Displays the URL lists for the DAP record.

Add—Click to add the selected URL list from the drop-down list to the URL area on the right.

Delete—Click to delete the selected URL list from the URL list area. You cannot delete a URL list from the security appliance unless you first delete it from DAP records.

Access Method Tab—Lets you configure the type of remote access permitted.

Unchanged—Continue with the current remote access method.

AnyConnect Client—Connect using the Cisco AnyConnect VPN Client.

Web-Portal—Connect with clientless VPN.

Both-default-Web-Portal—Connect via either clientless or the AnyConnect client, with a default of clientless.

Both-default-AnyConnect Client—Connect via either clientless or the AnyConnect client, with a default of AnyConnect.

Modes

The following table shows the modes in which this feature is available:

Firewall Mode
Security Context
Routed
Transparent
Single
Multiple
Context
System


Add/Edit AAA Attributes

Figure 37-4 shows the Add AAA Attribute dialog box.

Figure 37-4 Add AAA Attribute Dialog Box

To configure AAA attributes as selection criteria for DAP records, in the Add/Edit AAA Attributes dialog box, set the Cisco, LDAP, or RADIUS attributes that you want to use. You can set these attributes either to = or != the value you enter. There is no limit for the number of AAA attributes for each DAP record. For detailed information about AAA attributes, see AAA Attribute Definitions.

Fields

AAA Attributes Type—Use the drop-down list to select Cisco, LDAP or RADIUS attributes:

Cisco—Refers to user authorization attributes that are stored in the AAA hierarchical model. You can specify a small subset of these attributes for the AAA selection attributes in the DAP record.These include:

Group Policy —The group policy name associated with the VPN user session. Can be set locally on the security appliance or sent from a RADIUS/LDAP server as the IETF-Class (25) attribute. Maximum 64 characters.

IP Address—The assigned IP address for full tunnel VPN clients (IPsec, L2TP/IPsec, SSL VPN AnyConnect). Does not apply to Clientless SSL VPN, since there is no address assignment for clientless sessions.

Connection Profile—The connection or tunnel group name. Maximum 64 characters.

Username—The username of the authenticated user. Maximum 64 characters. Applies if you are using Local, RADIUS, LDAP authentication/authorization or any other authentication type (for example, RSA/SDI), NT Domain, etc).

=/!=—Equal to/Not equal to.

LDAP—The LDAP client (security appliance) stores all native LDAP response attribute value pairs in a database associated with the AAA session for the user. The LDAP client writes the response attributes to the database in the order in which it receives them. It discards all subsequent attributes with that name. This scenario might occur when a user record and a group record are both read from the LDAP server. The user record attributes are read first, and always have priority over group record attributes.

To support Active Directory group membership, the AAA LDAP client provides special handling of the LDAP memberOf response attribute. The AD memberOf attribute specifies the DN string of a group record in AD. The name of the group is the first CN value in the DN string. The LDAP client extracts the group name from the DN string and stores it as the AAA memberOf attribute, and in the response attribute database as the LDAP memberOf attribute. If there are additional memberOf attributes in the LDAP response message, then the group name is extracted from those attributes and is combined with the earlier AAA memberOf attribute to form a comma separated string of group names, also updated in the response attribute database.

In the case where the VPN remote access session to an LDAP authentication/authorization server returns the following three Active directory groups (memberOf enumerations):

cn=Engineering,ou=People,dc=company,dc=com

cn=Employees,ou=People,dc=company,dc=com

cn=EastCoastast,ou=People,dc=company,dc=com

the ASA processes three Active Directory groups: Engineering, Employees, and EastCoast which could be used in any combination as aaa.ldap selection criteria.

LDAP attributes consist of an attribute name and attribute value pair in the DAP record. The LDAP attribute name is syntax/case sensitive. If for example you specify LDAP attribute Department instead of what the AD server returns as department, the DAP record will not match based on this attribute setting.


Note To enter multiple values in the Value field, use the semicolon (;) as the delimiter. For example:

eng;sale; cn=Audgen VPN,ou=USERS,o=OAG


RADIUS—The RADIUS client stores all native RADIUS response attribute value pairs in a database associated with the AAA session for the user. The RADIUS client writes the response attributes to the database in the order in which it receives them. It discards all subsequent attributes with that name. This scenario might occur when a user record and a group record are both read from the RADIUS server. The user record attributes are read first, and always have priority over group record attributes.

RADIUS attributes consist of an attribute number and attribute value pair in the DAP record. See Security Appliance Supported RADIUS Attributes and Values for a table that lists RADIUS attributes that the security appliance supports.


Note For RADIUS attributes, DAP defines the Attribute ID = 4096 + RADIUS ID.

For example:

The RADIUS attribute "Access Hours" has a Radius ID = 1, therefore DAP attribute value = 4096 + 1 = 4097.

The RADIUS attribute "Member Of" has a Radius ID = 146, therefore DAP attribute value = 4096 + 146 = 4242.


LDAP and RADIUS attributes include:

Attribute ID—Names/numbers the attribute. Maximum 64 characters.

Value—The attribute name (LDAP) or number (RADIUS).

To enter multiple values in the Value field, use the semicolon (;) as the delimiter. For example:

eng;sale; cn=Audgen VPN,ou=USERS,o=OAG

=/!=—Equal to/Not equal to.

LDAP includes the Get AD Groups button. This button queries the Active Directory LDAP server for the list of groups the user belong to (memberOf enumerations). It retrieves the AD groups using the CLI show-ad-groups command in the background

The show ad-groups command applies only to Active Directory servers using LDAP. Use this command to display AD groups that you can use for dynamic access policy AAA selection criteria.

The default time that the security appliance waits for a response from the server is 10 seconds. You can adjust this time using the group-search-timeout command in aaa-server host configuration mode.


Note If the Active Directory server has a large number of groups, the output of the show ad-groups command might be truncated based on limitations to the amount of data the server can fit into a response packet. To avoid this problem, use the filter option to reduce the number of groups reported by the server.


Modes

The following table shows the modes in which this feature is available:

Firewall Mode
Security Context
Routed
Transparent
Single
Multiple
Context
System


Retrieving Active Directory Groups

Figure 37-5 shows the Retrieve AD Groups from Selected AD Server Group pane.

Figure 37-5 Retrieve AD Groups Dialog Box

You can query an Active Directory server for available AD groups in this pane. This feature applies only to Active Directory servers using LDAP. Use the group information to specify dynamic access policy AAA selection criteria.

You can change the level in the Active Directory hierarchy where the search begins by changing the Group Base DN in the Edit AAA Server pane. You can also change the time that the security appliance waits for a response from the server in the window. To configure these features, choose
Configuration > Remote Access VPN > AAA/Local Users > AAA Server Groups > Edit AAA Server.


Note If the Active Directory server has a large number of groups, the list of AD groups retrieved may be truncated based on limitations of the amount of data the server can fit into a response packet. To avoid this problem, use the filter feature to reduce the number of groups reported by the server.


Fields

AD Server Group—The name of the AAA server group to retrieve AD groups.

Filter By—Specify a group or the partial name of a group to reduce the groups displayed.

Group Name—A list of AD groups retrieved from the server.

Modes

The following table shows the modes in which this feature is available:

Firewall Mode
Security Context
Routed
Transparent
Single
Multiple
Context
System


Add/Edit Endpoint Attributes

Figure 37-6 shows the Add Endpoint Attributes dialog box.

Figure 37-6 Add Endpoint Attributes Dialog Box

Endpoint attributes contain information about the endpoint system environment, posture assessment results, and applications. The security appliance dynamically generates a collection of endpoint attributes during session establishment, and stores these attributes in a database associated with the session. There is no limit for the number of endpoint attributes for each DAP record.

Each DAP record specifies the endpoint selection attributes that must be satisfied for the security appliance to select it. The security appliance selects only DAP records that satisfy every condition configured.

For detailed information about Endpoint attributes, see Endpoint Attribute Definitions.

To configure endpoint attributes as selection criteria for DAP records, in the Add/Edit Endpoint Attribute dialog box, set components. These components change according to the attribute type you select.

Fields

Endpoint Attribute Type—Choose from the drop-down list the endpoint attribute you want to set. Options include Antispyware, Antivirus, Application, AnyConnect, File, NAC, Operating System, Personal Firewall, Process, Registry, VLAN, and Priority.

Endpoint attributes include these components, but not all attributes include all components. The following descriptions show (in parentheses) the attributes to which each component applies.

Exists/Does not exist buttons (Antispyware, Antivirus, Application, File, NAC, Operating System, Personal Firewall, Process, Registry, VLAN, Priority)— Click the appropriate button to indicate whether the selected endpoint attribute and its accompanying qualifiers (fields below the Exists/Does not exist buttons) should be present or not.

Vendor ID (Antispyware, Antivirus, Personal Firewall)—Identify the application vendor.

Vendor Description (Antispyware, Antivirus, Personal Firewall)—Provide text that describes the application vendor.

Version (Antispyware, Antivirus, Personal Firewall)—Identify the version of the application, and specify whether you want the endpoint attribute to be equal to/not equal to that version.

Last Update (Antispyware, Antivirus, File)—Specify the number of days since the last update. You might want to indicate that an update should occur in less than (<) or more than (>) the number of days you enter here.

Client Type (Application)—Indicate the type of remote access connection, AnyConnect, Clientless, Cut-through Proxy, IPsec, or L2TP.

Client Version (AnyConnect) — AnyConnect client version number. You can use this field to evaluate the AnyConnect client version on mobile devices, such as mobile phones and tablets, or desktop and laptop devices.

Checksum (File)—Select the file and click the Compute Checksum button to arrive at this value.

Compute CRC32 Checksum (File) — Use this calculator to determine the checksum value of a file.

Device Type (AnyConnect) — If you selected the Platform checkbox and selected the Apple iOS or Android platform, you can check the Device Type checkbox.

When you specify Android in the Platform field, you will be able to pick from a list of supported Android devices. When you specify Apple iOS in the Platform field you will be able to pick from a list of supported Apple devices. In both cases, the proper Android or Apple iOS device type information is substituted for the device type you choice from the list box.

If you have a supported device which is not listed in the Device Type field, you can enter the Android or Apple iOS device type information in the Device Type field. The most reliable way to obtain the device type information is to install the AnyConnect client on the endpoint and perform a DAP Trace. In the DAP trace results, look for the value of endpoint.anyconnect.devicetype. That is the value that you need to enter in the Device Type field.

Device Unique ID (AnyConnect) — If you selected the Platform checkbox and selected the Apple iOS or Android platform, you can check the Device Unique ID checkbox.

The Device Unique ID distinguishes individual devices allowing you to set policies for a particular mobile device. To obtain a device's unique ID you will need the device to connect to the ASA and perform a DAP trace.

OS Version (Operating System) —Windows (various), MAC, Linux, Pocket PC.

Platform— (AnyConnect) Operating system name. You can use this field to evaluate the operating system on mobile devices, such as mobile phones and tablets, as well as the operating system on desktop and laptop devices. Selecting Apple iOS or Android platforms activates the additional attribute fields for Device Type and Device Unique ID.

Posture Status (NAC) — Contains the posture token string received from ACS.

Platform Version (AnyConnect) — The operating system version number. If you want to create a DAP record that contains this attribute, be sure to also specify a Platform in the Platform field.

Service Pack (Operating System)—Identify the service pack for the operating system.

Endpoint ID (File, Process, Registry)—A string that identifies an endpoint for files, processes or registry entries. DAP uses this ID to match Cisco Secure Desktop host scan attributes for DAP selection. You must configure Host Scan before you configure this attribute. When you configure Host Scan, the configuration displays in this pane, so you can select it, reducing the possibility of errors in typing or syntax.

Path (Process, Policy)—Configure Host Scan before you configure this attribute. When you configure Host Scan, the configuration displays in this pane, so you can select it, reducing the possibility of errors in typing or syntax.

Value (Registry)—dword or string

Caseless (Registry)—Select to disregard case in registry entries.

VLAN ID (VLAN)—A valid 802.1q number ranging from 1 to 4094

VLAN Type (VLAN)—Possible values include the following:

ACCESS

Posture assessment passed

STATIC

No posture assessment applied

TIMEOUT

Posture assessment failed due to no response

AUTH

Posture assessment still active

GUEST

Posture assessment passed, switch to guest VLAN

QUARANTINE

Posture assessment failed, switch to quarantine VLAN

ERROR

Posture assessment failed due to fatal error


Policy (Location)—Enter the Cisco Secure Desktop Microsoft Windows location profile, case sensitive.

Modes

The following table shows the modes in which this feature is available:

Firewall Mode
Security Context
Routed
Transparent
Single
Multiple
Context
System


Guide

This section provides information about constructing logical expressions for AAA or Endpoint attributes. Be aware that doing so requires sophisticated knowledge of Lua (www.lua.org).

In the Advanced field you enter free-form Lua text that represents AAA and/or endpoint selection logical operations. ASDM does not validate text that you enter here; it just copies this text to the DAP policy file, and the security appliance processes it, discarding any expressions it cannot parse.

This option is useful for adding selection criteria other than what is possible in the AAA and endpoint attribute areas above. For example, while you can configure the security appliance to use AAA attributes that satisfy any, all, or none of the specified criteria, endpoint attributes are cumulative, and must all be satisfied. To let the security appliance employ one endpoint attribute or another, you need to create appropriate logical expressions in Lua and enter them here.

For a list of AAA Selection attributes, including proper name syntax for creating logical expressions, see Table 37-1.

For a list of endpoint selection attributes, including proper name syntax for creating logical expressions, see Table 37-3.

The following sections provide detailed explanations of creating Lua EVAL expressions, as well as examples.

Syntax for Creating Lua EVAL Expressions

Constructing DAP EVAL Expressions

The DAP CheckAndMsg Function

Checking for a Single Antivirus Program

Checking for Antivirus Definitions Within the Last 10 Days

Checking for a Hotfix on the User PC

Checking for Antivirus Programs

Checking for Antivirus Programs and Definitions Older than 1 1/2 Days

Additional Lua Functions

OU-Based Match Example

Group Membership Example

Antivirus Example

Antispyware Example

Firewall Example

Antivirus, Antispyware, or any Firewall Example

CheckAndMsg with Custom Function Example

Further Information on Lua

Syntax for Creating Lua EVAL Expressions

This section provides information about the syntax for creating Lua EVAL expressions.


Note If you must use Advanced mode, we recommend that you use EVAL expressions whenever possible for reasons of clarity, which makes verifying the program straightforward.


EVAL(<attribute> , <comparison>, {<value> | <attribute>}, [<type>])

<attribute>

AAA attribute or an attribute returned from Cisco Secure Desktop, see Table 37-1 and Table 37-3 for attribute definitions

<comparison>

One of the following strings (quotation marks required)

 

"EQ"

equal

 

"NE"

not equal

 

"LT"

less than

 

"GT"

greater than

 

"LE"

less than or equal

 

"GE"

greater than or equal

<value>

A string in quotation marks that contains the value to compare the attribute against

<type>

One of the following strings (quotation marks required)

 

"string"

case-sensitive string comparison

 

"caseless"

case-insensitive string comparison

 

"integer"

number comparison, converts string values to numbers

 

"hex"

number comparison using hexadecimal values, converts hex string to hex numbers

 

"version"

compares versions of the form X.Y.Z. where X, Y, and Z are numbers


Example:

EVAL(endpoint.os.version, "EQ", "Windows XP", "string")

Constructing DAP EVAL Expressions

Study these examples for help in creating logical expressions in Lua.

This endpoint expression tests for a match on CLIENTLESS OR CVC client types:

(EVAL(endpoint.application.clienttype,"EQ","CLIENTLESS") or 
EVAL(endpoint.application.clienttype, "EQ","CVC"))
 
   

This endpoint expression tests for Norton Antivirus versions 10.x but excludes 10.5.x:

(EVAL(endpoint.av["NortonAV"].version, "GE", "10","version") and 
(EVAL(endpoint.av["NortonAV"].version,"LT", "10.5", "version") or 
EVAL(endpoint.av["NortonAV"].version, "GE", "10.6", "version")))

The DAP CheckAndMsg Function

CheckAndMsg is a Lua function that you can configure DAP to call. It generates a user message based on a condition.

You use ASDM to configure CheckAndMsg through the Advanced field in DAP. The security appliance displays the message to the user only when the DAP record containing the LUA CheckAndMsg function is selected and results in a clientless SSL VPN or AnyConnect termination.

The syntax of the CheckAndMsg function follows:

CheckAndMsg(value, "<message string if value is true>", "<message string if value if 
false>")
 
   

Be aware of the following when creating CheckAndMsg functions:

CheckAndMsg returns the value passed in as its first argument.

Use the EVAL function as the first argument if you do not want to use string comparison. For example:

(CheckAndMsg((EVAL(...)) , "true msg", "false msg"))
 
   

CheckandMsg returns the result of the EVAL function and the security appliances uses it to determine whether to select the DAP record. If the record is selected and results in termination, the security appliance displays the appropriate message.

Checking for a Single Antivirus Program

This example checks if a single antivirus program, in this case McAfee, is installed on the user PC, and displays a message if it is not.

(CheckAndMsg(EVAL(endpoint.av["McAfeeAV"].exists,"NE","true"),"McAfee AV was not 
found on your computer", nil))

Checking for Antivirus Definitions Within the Last 10 Days

This example checks antivirus definitions within the last 10 days (864000 sec), in particular the last update of the McAfee AV dat file, and displays a message to a user lacking the appropriate update that they need an antivirus update:

((CheckAndMsg(EVAL(endpoint.av["McAfeeAV"].lastupdate,"GT","864000","integer"),"AV 
Update needed! Please wait for the McAfee AV till it loads the latest dat file.",nil) ))

Checking for a Hotfix on the User PC

This example checks for a specific hotfix. If a user does not have the hotfix on their PC, a message that it is not installed displays.

(not CheckAndMsg(EVAL(endpoint.os.windows.hotfix["KB923414"],"EQ","true"),nil,"The 
required hotfix is not installed on your PC."))
 
   

or you could define it this way (which makes more sense):

(CheckAndMsg(EVAL(endpoint.os.windows.hotfix["KB923414"],"NE","true"),"The required hotfix 
is not installed on your PC.",nil))
 
   

You can build the expression in this example because the debug dap trace returns:

endpoint.os.windows.hotfix["KB923414"] = "true";

Checking for Antivirus Programs

You can configure messages so that the end user is aware of and able to fix problems with missing or not running AVs. As a result, if access is denied, the security appliance collects all messages for the DAP that caused the "terminate" condition and displays them in the browser on the logon page. If access is allowed, the security appliance displays all messages generated in the process of DAP evaluation on the portal page.

The following example shows how to use this feature to check on the Norton Antivirus program.


Step 1 Copy and paste the following Lua expression into the Advanced field of the Add/Edit Dynamic Access Policy pane (click the double arrow on the far right to expand the field).

(CheckAndMsg(EVAL(endpoint.av["NortonAV"].exists, "EQ", "false"),"Your Norton AV was found 
but the active component of it was not enabled", nil) or 
CheckAndMsg(EVAL(endpoint.av["NortonAV"].exists, "NE", "true"),"Norton AV was not found on 
your computer", nil) )
 
   

Step 2 In that same Advanced field, click the OR button.

Step 3 In the Access Attributes section below, in the leftmost tab, Action, click Terminate.

Step 4 Connect from a PC that does not have or has disabled Norton Antivirus.

The expected result is that the connection is not allowed and the message appears as a blinking ! point.

Step 5 Click the blinking ! to see the message.


Checking for Antivirus Programs and Definitions Older than 1 1/2 Days

This example checks for the presence of the Norton and McAfee antivirus programs, and whether the virus definitions are older than 1 1/2 days (10,000 seconds). If the definitions are older than 1 1/2 days, the security appliance terminates the session with a message and links for remediation. To accomplish this task, perform the following steps.


Step 1 Copy and paste the following Lua expression into the Advanced field of the Add/Edit Dynamic Access Policy pane (click the double arrow on the far right to expand the field):

((EVAL(endpoint.av["NortonAV"].exists,"EQ","true","string") and 
CheckAndMsg(EVAL(endpoint.av["NortonAV"].lastupdate,"GT","10000",integer"),To 
remediate <a href='http://www.symantec.com'>Click this link </a>",nil)) or
(EVAL(endpoint.av["McAfeeAV"].exists,"EQ","true","string") and CheckAndMsg(EVAL(endpoint.av["McAfeeAV"].lastupdate,"GT","10000",integer"),To remediate <a href='http://www.mcafee.com'>Click this link</a>",nil))

Step 2 In that same Advanced field, click AND.

Step 3 In the Access Attributes section below, in leftmost tab, Action, click Terminate.

Step 4 Connect from a PC that has Norton and McAfee antivirus programs with versions that are older than
1 1/2 days.

The expected result is that the connection is not allowed and the message appears as a blinking ! point.

Step 5 Click the blinking ! to see the message and links for remediation.


Additional Lua Functions

When working with dynamic access policies for clientless SSL VPN, you might need additional flexibility of match criteria. For example, you might want to apply a different DAP based on the following:

Organizational Unit (OU) or other level of the hierarchy for the user object

Group Name that follows a naming convention but has many possible matches—you might require the ability to use a wildcard on group names.

You can accomplish this flexibility by creating a Lua logical expression in the Advanced section of the DAP pane in ASDM.

OU-Based Match Example

DAP can use many attributes returned from an LDAP server in a logical expression. See the DAP trace section for example output of this, or run a debug dap trace.

The LDAP server returns the user Distinguished Name (DN). This implicitly identifies where in the directory the user object is located. For example, if the user DN is CN=Example User,OU=Admins,dc=cisco,dc=com this user is located in OU=Admins,dc=cisco,dc=com. If all administrators are in this OU (or any container below this level) you can use a logical expression to match on this criteria as follows:

assert(function()
   if ( (type(aaa.ldap.distinguishedName) == "string") and
        (string.find(aaa.ldap.distinguishedName, "OU=Admins,dc=cisco,dc=com$") ~= nil) ) 
then
       return true
   end
   return false
end)()
 
   

In this example, the string.find function allows for a regular expression. Use the $ at the end of the string to anchor this string to the end of the distinguishedName field.

Group Membership Example

You can create a basic logical expression for pattern matching of AD group membership. Because users can be members of multiple groups, DAP parses the response from the LDAP server into separate entries in a table. You need an advanced function to accomplish the following:

Compare the memberOf field as a string (in the event the user belongs to only one group).

Iterate through each returned memberOf field if the returned data is of type "table".

The function we have written and tested for this purpose is shown below. In this example, if a user is a member of any group ending with "-stu" they match this DAP.

assert(function()
   local pattern = "-stu$"
   local attribute = aaa.ldap.memberOf
   if ((type(attribute) == "string") and
       (string.find(attribute, pattern) ~= nil)) then
       return true
   elseif (type(attribute) == "table") then
       local k, v
       for k, v in pairs(attribute) do
           if (string.find(v, pattern) ~= nil) then
               return true
           end
       end
   end
   return false
end)()

Antivirus Example

The following example uses a custom function to check if CSD detects any antivirus software.

assert(function()
    for k,v in pairs(endpoint.av) do
         if (EVAL(v.exists, "EQ", "true", "string")) then
              return true
         end
    end
    return false
end)()

Antispyware Example

The following example uses a custom function to check if CSD detects any antispyware.

assert(function()
    for k,v in pairs(endpoint.as) do
         if (EVAL(v.exists, "EQ", "true", "string")) then
              return true
         end
    end
    return false
end)()

Firewall Example

The following example uses a custom function to check if CSD detects a firewall.

assert(function()
    for k,v in pairs(endpoint.fw) do
         if (EVAL(v.exists, "EQ", "true", "string")) then
              return true
         end
    end
    return false
end)()

Antivirus, Antispyware, or any Firewall Example

The following example uses a custom function to check if CSD detects any antivirus, antispyware, or any firewall.

assert(function()
       function check(antix)
           if (type(antix) == "table") then
               for k,v in pairs(antix) do
                   if (EVAL(v.exists, "EQ", "true", "string")) then
                       return true
                   end
               end
           end
           return false
       end
       return (check(endpoint.av) or check(endpoint.fw) or check(endpoint.as))
   end)()

CheckAndMsg with Custom Function Example

You can use the following function to deny access in the absence of an antivirus program. Use it with a DAP that has Action set to terminate.

assert( function() 
for k,v in pairs(endpoint.av) do 
	if (EVAL(v.exists, "EQ", "true", "string")) then 
		return false 
	end
	end
	return CheckAndMsg(true, "Please install antivirus software before connecting.", nil)
end)()
 
   

If a user lacking an antivirus program attempts to log in, DAP displays the following message:

Please install antivirus software before connecting.

Further Information on Lua

You can find detailed LUA programming information at http://www.lua.org/manual/5.1/manual.html.

Operator for Endpoint Category

You can configure multiple instances of each type of endpoint. In this pane, set each type of endpoint to require only one instance of a type (Match Any = OR) or to have all instances of a type (Match All = AND).

If you configure only one instance of an endpoint category, you do not need to set a value.

For some endpoint attributes, it makes no sense to configure multiple instances. For example, no users have more than one running OS.

You are configuring the Match Any/Match All operation within each endpoint type.

The security appliance evaluates each type of endpoint attribute, and then performs a logical AND operation on all of the configured endpoints. That is, each user must satisfy the conditions of ALL of the endpoints you configure, as well as the AAA attributes.

DAP Examples

The following sections provide examples of useful dynamic access policies.

Using DAP to Define Network Resources

Using DAP to Apply a WebVPN ACL

Enforcing CSD Checks and Applying Policies via DAP

Using DAP to Define Network Resources

This example shows how to configure dynamic access policies as a method of defining network resources for a user or group. The DAP policy named Trusted_VPN_Access permits clientless and AnyConnect VPN access. The policy named Untrusted_VPN_Access permits only clientless VPN access. Table 37-4 summarizes the configuration of each of these policies.

The ASDM path is Configuration > Remote Access VPN > Clientless SSL VPN Access > Dynamic Access Policies > Add/Edit Dynamic Access Policy > Endpoint

Table 37-4 A Simple DAP Configuration for Network Resources

Attribute
Trusted_VPN_Access 
Untrusted_VPN_Access 

Endpoint Attribute Type Policy

Trusted

Untrusted

Endpoint Attribute Process

ieexplore.exe

Advanced Endpoint Assessment

AntiVirus= McAfee Attribute

 

CSD Location

Trusted

Untrusted

LDAP memberOf

Engineering, Managers

Vendors

ACL

 

Web-Type ACL

Access

AnyConnect and Web Portal

Web Portal


Using DAP to Apply a WebVPN ACL

DAP can directly enforce a subset of access policy attributes including Network ACLs (for IPsec and AnyConnect), clientless SSL VPN Web-Type ACLs, URL lists, and Functions. It cannot directly enforce, for example, a banner or the split tunnel list, which the group policy enforces. The Access Policy Attributes tabs in the Add/Edit Dynamic Access Policy pane provide a complete menu of the attributes DAP directly enforces.

Active Directory/LDAP stores user group policy membership as the "memberOf" attribute in the user entry. You can define a DAP such that for a user in AD group (memberOf) = Engineering the security appliance applies a configured Web-Type ACL. To accomplish this task, perform the following steps:


Step 1 Navigate to the Add AAA attributes pane (Configuration > Remote Access VPN > Clientless SSL VPN Access > Dynamic Access Policies > Add/Edit Dynamic Access Policy > AAA Attributes section > Add AAA Attribute).

Step 2 For the AAA Attribute type, use the drop-down menu to choose LDAP.

Step 3 In the Attribute ID field, enter memberOf, exactly as you see it here. Case is important.

Step 4 In the Value field, use the drop-down menu to choose =, and in the adjacent field enter Engineering.

Step 5 In the Access Policy Attributes area of the pane, click the Web-Type ACL Filters tab.

Step 6 Use the Web-Type ACL drop-down menu to select the ACL you want to apply to users in the AD group (memberOf) = Engineering.


Enforcing CSD Checks and Applying Policies via DAP

This example creates a DAP that checks that a user belongs to two specific AD/LDAP groups (Engineering and Employees) and a specific ASA tunnel group. It then applies an ACL to the user.

The ACLs that DAP applies control access to the resources. They override any ACLS defined the group policy on the security appliance. In addition, the security appliance applied the regular AAA group policy inheritance rules and attributes for those that DAP does not define or control, examples being split tunneling lists, banner, and DNS. To accomplish this task, perform the following steps.


Step 1 Navigate to the Add AAA attributes pane (Configuration > Remote Access VPN > Clientless SSL VPN Access > Dynamic Access Policies > Add/Edit Dynamic Access Policy > AAA Attributes section > Add AAA Attribute).

Step 2 For the AAA Attribute type, use the drop-down menu to choose LDAP.

Step 3 In the Attribute ID field, enter memberOf, exactly as you see it here. Case is important.

Step 4 In the Value field, use the drop-down menu to choose =, and in the adjacent field enter Engineering.

Step 5 In the Attribute ID field, enter memberOf, exactly as you see it here. Case is important.

Step 6 In the Value field, use the drop-down menu to select =, and in the adjacent field enter Employees.

Step 7 For the AAA attribute type, use the drop-down menu to choose Cisco.

Step 8 Check the Tunnel group box, use the drop-down menu to choose =, and in the adjacent drop-down list select the appropriate tunnel group (connection policy).

Step 9 In the Network ACL Filters tab of the Access Policy Attributes area, choose the ACLs to apply to users who meet the DAP criteria defined in the previous steps.