Table Of Contents

Login Password Retry Lockout

Contents

Prerequisites for Login Password Retry Lockout

Restrictions for Login Password Retry Lockout

Information About Login Password Retry Lockout

Locking Out a Local AAA User Account

How to Configure Login Password Retry Lockout

Configuring Login Password Retry Lockout

Unlocking a Locked-Out User

Clearing the Unsuccessful Attempts of a User

Monitoring and Maintaining Login Password Retry Lockout

Configuration Examples for Login Password Retry Lockout

Login Password Retry Lockout: Example

show aaa local user lockout Command: Example

Additional References

Related Documents

Standards

MIBs

RFCs

Technical Assistance

Command Reference

Glossary

Login Password Retry Lockout

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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.

Feature History for Login Password Retry Lockout

Release	Modification
12.3(14)T	This feature was introduced.

Finding Support Information for Platforms and Cisco IOS Software Images

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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

•Command Reference

•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:

•Locking Out a Local AAA User Account

Locking Out 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.

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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. If the user can change to the root privilege (level 15), that user is able to act as a system administrator.

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

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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.

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How to Configure Login Password Retry Lockout

This section contains the following procedures:

•Configuring Login Password Retry Lockout

•Unlocking a Locked-Out User

•Clearing the Unsuccessful Attempts of a User

•Monitoring and Maintaining Login Password Retry Lockout

Configuring Login Password Retry Lockout

To configure Login Password Retry Lockout, 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	Method list for login, specifying to authenticate using the local AAA user database.

Unlocking a Locked-Out User

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

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

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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 Attempts of a User

To clear the unsuccessful 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

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

SUMMARY STEPS

1. enable

2. show aaa local user locked

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 locked Example: Router# show aaa local user locked	Displays a list of the locked-out users.

Configuration Examples for Login Password Retry Lockout

This section provides the following configuration examples:

•Login Password Retry Lockout: Example

•show aaa local user lockout Command: Example

Login Password Retry Lockout: Example

The following show running-config command output illustrates that the maximum number of failed user attempts has been set for 2:

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

show aaa local user lockout Command: Example

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

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, Release 12.3T

Standards

Standards	Title
No new or modified standards are supported by this feature, and support for existing standards has not been modified by this feature.	—

MIBs

MIBs	MIBs Link
No new or modified MIBs are supported by this feature, and support for existing MIBs has not been modified by this feature.	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
No new or modified RFCs are supported by this feature, and support for existing RFCs has not been modified by this feature.	—

Technical Assistance

Description	Link
Technical Assistance Center (TAC) home page, containing 30,000 pages of searchable technical content, including links to products, technologies, solutions, technical tips, and tools. Registered Cisco.com users can log in from this page to access even more content.	http://www.cisco.com/public/support/tac/home.shtml

Command Reference

The following commands are introduced or modified in the feature or features documented in this module. For information about these commands, see the Cisco IOS Security Command Reference at http://www.cisco.com/en/US/docs/ios/security/command/reference/sec_book.html. For information about all Cisco IOS commands, go to the Command Lookup Tool at http://tools.cisco.com/Support/CLILookup or to the Cisco IOS Master Commands List.

•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.

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Note Refer to Internetworking Terms and Acronyms for terms not included in this glossary.

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Any Internet Protocol (IP) addresses used in this document are not intended to be actual addresses. Any examples, command display output, and figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses in illustrative content is unintentional and coincidental.

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