Cisco IOS Security Configuration Guide: Securing User Services, Release 12.2SR
Login Password Retry Lockout
Downloads: This chapterpdf (PDF - 150.0KB) The complete bookPDF (PDF - 6.56MB) | Feedback

Login Password Retry Lockout

Table Of Contents

Login Password Retry Lockout

Finding Feature Information

Contents

Prerequisites for Login Password Retry Lockout

Restrictions for Login Password Retry Lockout

Information About Login Password Retry Lockout

Lock Out of a Local AAA User Account

How to Configure Login Password Retry Lockout

Configuring Login Password Retry Lockout

Unlocking a Login Locked-Out User

Clearing the Unsuccessful Login Attempts of a User

Monitoring and Maintaining Login Password Retry Lockout Status

Examples

Configuration Examples for Login Password Retry Lockout

Displaying the Login Password Retry Lockout Configuration: Example

Additional References

Related Documents

Standards

MIBs

RFCs

Technical Assistance

Feature Information for Login Password Retry Lockout

Glossary


Login Password Retry Lockout


First Published: March 24, 2005
Last Updated: November 20, 2009

The Login Password Retry Lockout feature allows system administrators to lock out a local authentication, authorization, and accounting (AAA) user account after a configured number of unsuccessful attempts by the user to log in.

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest feature information and caveats, see the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the "Feature Information for Login Password Retry Lockout" section.

Use Cisco Feature Navigator to find information about platform support and Cisco IOS and Catalyst OS software image support. To access Cisco Feature Navigator, go to http://tools.cisco.com/ITDIT/CFN/jsp/index.jsp. An account on Cisco.com is not required.

Contents

Prerequisites for Login Password Retry Lockout

Restrictions for Login Password Retry Lockout

Information About Login Password Retry Lockout

How to Configure Login Password Retry Lockout

Configuration Examples for Login Password Retry Lockout

Additional References

Feature Information for Login Password Retry Lockout

Glossary

Prerequisites for Login Password Retry Lockout

You must be running a Cisco IOS image that contains the AAA component.

Restrictions for Login Password Retry Lockout

Authorized users can lock themselves out because there is no distinction between an attacker who is guessing passwords and an authorized user who is entering the password incorrectly multiple times.

A denial of service (DoS) attack is possible; that is, an authorized user could be locked out by an attacker if the username of the authorized user is known to the attacker.

Information About Login Password Retry Lockout

To configure the Login Password Retry Lockout feature, you should understand the following concept:

Lock Out of a Local AAA User Account

Lock Out of a Local AAA User Account

The Login Password Retry Lockout feature allows system administrators to lock out a local AAA user account after a configured number of unsuccessful attempts by the user to log in using the username that corresponds to the AAA user account. A locked-out user cannot successfully log in again until the user account is unlocked by the administrator.

A system message is generated when a user is either locked by the system or unlocked by the system administrator. The following is an example of such a system message:

%AAA-5-USER_LOCKED: User user1 locked out on authentication failure.

The system administrator cannot be locked out.


Note The system administrator is a special user who has been configured using the maximum privilege level (root privilege—level 15). A user who has been configured using a lesser privilege level can change the privilege level using the enable command. A user that can change to the root privilege (level 15) is able to act as a system administrator.


This feature is applicable to any login authentication method, such as ASCII, Challenge Handshake Authentication Protocol (CHAP), and Password Authentication Protocol (PAP).


Note No messages are displayed to users after authentication failures that are due to the locked status (that is, there is no distinction between a normal authentication failure and an authentication failure due to the locked status of the user).


How to Configure Login Password Retry Lockout

This section contains the following procedures:

Configuring Login Password Retry Lockout (optional)

Unlocking a Login Locked-Out User (optional)

Clearing the Unsuccessful Login Attempts of a User (optional)

Monitoring and Maintaining Login Password Retry Lockout Status (optional)

Configuring Login Password Retry Lockout

To configure the Login Password Retry Lockout feature, perform the following steps.

SUMMARY STEPS

1. enable

2. configure terminal

3. username name [privilege level] password encryption-type password

4. aaa new-model

5. aaa local authentication attempts max-fail number-of-unsuccessful-attempts

6. aaa authentication login default method

DETAILED STEPS

 
Command or Action
Purpose

Step 1 

enable

Example:

Router> enable

Enables privileged EXEC mode.

Enter your password if prompted.

Step 2 

configure terminal

Example:

Router# configure terminal

Enters global configuration mode.

Step 3 

username name [privilege level] password 
encryption-type password
Example:
Router(config)# username user1 privilege 15 
password 0 cisco

Establishes a username-based authentication system.

Step 4 

aaa new-model

Example:

Router(config)# aaa new-model

Enables the AAA access control model.

Step 5 

aaa local authentication attempts max-fail number-of-unsuccessful-attempts

Example:

Router(config)# aaa local authentication attempts max-fail 3

Specifies the maximum number of unsuccessful attempts before a user is locked out.

Step 6 

aaa authentication login default method

Example:

Router(config)# aaa authentication login default local

Sets the authentication, authorization, and accounting (AAA) authentication method at login. For example, aaa authentication login default local specifies the local AAA user database.

Unlocking a Login Locked-Out User

To unlock a login locked-out user, perform the following steps.


Note This task can be performed only by users having the root privilege (level 15).


SUMMARY STEPS

1. enable

2. clear aaa local user lockout {username username | all}

DETAILED STEPS

 
Command or Action
Purpose

Step 1 

enable

Example:

Router> enable

Enables privileged EXEC mode.

Enter your password if prompted.

Step 2 

clear aaa local user lockout {username username | all}

Example:

Router# clear aaa local user lockout username user1

Unlocks a locked-out user.

Clearing the Unsuccessful Login Attempts of a User

This task is useful for cases in which the user configuration was changed and the unsuccessful login attempts of a user that are already logged must be cleared.

To clear the unsuccessful login attempts of a user that have already been logged, perform the following steps.

SUMMARY STEPS

1. enable

2. clear aaa local user fail-attempts {username username | all}

DETAILED STEPS

 
Command or Action
Purpose

Step 1 

enable

Example:

Router> enable

Enables privileged EXEC mode.

Enter your password if prompted.

Step 2 

clear aaa local user fail-attempts {username username | all}

Example:

Router# clear aaa local user fail-attempts username user1

Clears the unsuccessful attempts of the user.

This command is useful for cases in which the user configuration was changed and the unsuccessful attempts that are already logged must be cleared.

Monitoring and Maintaining Login Password Retry Lockout Status

To monitor and maintain the status of the Login Password Retry Lockout configuration, perform the following steps.

SUMMARY STEPS

1. enable

2. show aaa local user lockout

DETAILED STEPS

 
Command or Action
Purpose

Step 1 

enable

Example:

Router> enable

Enables privileged EXEC mode.

Enter your password if prompted.

Step 2 

show aaa local user lockout

Example:

Router# show aaa local user lockout

Displays a list of the locked-out users for the current login password retry lockout configuration.

Examples

The following output shows that user1 is locked out:

Router# show aaa local user lockout

           Local-user          Lock time
           user1               04:28:49 UTC Sat Jun 19 2004

Configuration Examples for Login Password Retry Lockout

This section provides the following configuration examples:

Displaying the Login Password Retry Lockout Configuration: Example

Displaying the Login Password Retry Lockout Configuration: Example

The following show running-config command output illustrates that the maximum number of failed user attempts has been set for 2 as the login password retry lockout configuration:

Router # show running-config

Building configuration...

Current configuration : 1214 bytes
!
version 12.3
no service pad
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
!
hostname LAC-2
!
boot-start-marker
boot-end-marker
!
!
username sysadmin
username sysad privilege 15 password 0 cisco
username user1 password 0 cisco
aaa new-model
aaa local authentication attempts max-fail 2
!
!
aaa authentication login default local
aaa dnis map enable
aaa session-id common

Additional References

The following sections provide references related to Login Password Retry Lockout.

Related Documents

Related Topic
Document Title

Cisco IOS security commands

Cisco IOS Security Command Reference


Standards

Standards
Title

None


MIBs

MIBs
MIBs Link

None

To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:

http://www.cisco.com/go/mibs


RFCs

RFCs
Title

None


Technical Assistance

Description
Link

The Cisco Support website provides extensive online resources, including documentation and tools for troubleshooting and resolving technical issues with Cisco products and technologies.

To receive security and technical information about your products, you can subscribe to various services, such as the Product Alert Tool (accessed from Field Notices), the Cisco Technical Services Newsletter, and Really Simple Syndication (RSS) Feeds.

Access to most tools on the Cisco Support website requires a Cisco.com user ID and password.

http://www.cisco.com/techsupport


Feature Information for Login Password Retry Lockout

Table 1 lists the release history for this feature.

Not all commands may be available in your Cisco IOS software release. For release information about a specific command, see the command reference documentation.

Use Cisco Feature Navigator to find information about platform support and software image support. Cisco Feature Navigator enables you to determine which Cisco IOS and Catalyst OS software images support a specific software release, feature set, or platform. To access Cisco Feature Navigator, go to http://tools.cisco.com/ITDIT/CFN/jsp/index.jsp. An account on Cisco.com is not required.


Note Table 1 lists only the Cisco IOS software release that introduced support for a given feature in a given Cisco IOS software release train. Unless noted otherwise, subsequent releases of that Cisco IOS software release train also support that feature.


Table 1 Feature Information for Login Password Retry Lockout 

Feature Name
Releases
Feature Information

Login Password Retry Lockout

12.3(14)T 12.2(33)SRE

The Login Password Retry Lockout feature allows system administrators to lock out a local AAA user account after a configured number of unsuccessful attempts by the user to log in.

This feature was introduced in Cisco IOS Release 12.3(14)T.

This feature was integrated into Cisco IOS Release 12.2(33)SRE.

The following commands were introduced or modified: aaa local authentication attempts max-fail, clear aaa local user fail-attempts, clear aaa local user lockout.


Glossary

local AAA method—Method by which it is possible to configure a local user database on a router and to have AAA provision authentication or authorization of users from this database.

local AAA user—User who is authenticated using the local AAA method.