Maximum lifetime for service ticket

Applies To: Windows Server 2008, Windows Server 2008 R2

This security policy reference topic for the IT professional describes the best practices, location, values, and security considerations for this policy setting.

Reference

The Maximum lifetime for service ticket policy setting determines the maximum number of minutes that a granted session ticket can be used to access a particular service. The value must be 10 minutes or greater, and it must be less than or equal to the value of the Maximum lifetime for service ticket policy setting.

The possible values for this Group Policy setting are:

• A user-defined number of minutes from 10 through 99,999, or 0 (in which case service tickets do not expire).

• Not defined.

If a client presents an expired session ticket when it requests a connection to a server, the server returns an error message. The client must request a new session ticket from the Kerberos V5 KDC. After a connection is authenticated, however, it no longer matters whether the session ticket remains valid. Session tickets are used only to authenticate new connections with servers. Ongoing operations are not interrupted if the session ticket that authenticated the connection expires during the connection.

If the value for this policy setting is too high, users might be able to access network resources outside of their logon hours. In addition, users whose accounts have been disabled might be able to continue accessing network services by using valid service tickets that were issued before their account was disabled. If the value is set to 0, service tickets never expire.

Best practices

1. It is advisable to set Maximum lifetime for service ticket to 600 minutes.

Location

GPO_name\Computer Configuration\Windows Settings\Security Settings\Account Policies\Kerberos Policy\

Default Values

Operating system version differences

There are no differences in this policy for Windows versions beginning with Windows Server 2003.

Security considerations

This section describes how an attacker might exploit a feature or its configuration, how to implement the countermeasure, and the possible negative consequences of countermeasure implementation.

Vulnerability

If you configure the value for the Maximum lifetime for service ticket setting too high, users might be able to access network resources outside of their logon hours. Also, users whose accounts were disabled might continue to have access to network services with valid service tickets that were issued before their accounts were disabled.

Countermeasure

Configure the Maximum lifetime for service ticket setting to 600 minutes.

Potential impact

None. This is the default configuration.