Microsoft Forefront Unified Access Gateway 2010 (UAG) provides cross-site single sign-on (SSO) functionality. This lets users who log on to one Forefront UAG site access additional Forefront UAG sites that are configured in the cross-site list without having to reauthenticate. Forefront UAG 2010 also lets an administrator define session time-out values in the portal trunk properties.
In a Forefront UAG site that's configured for cross-site SSO, a preauthenticated user who has an existing cross-site authorization cookie may be permitted access even if the user session has exceeded the defined portal trunk session time-out period.
To resolve this problem, install the service pack that is described in the following Microsoft Knowledge Base article:
2744025 Description of Forefront Unified Access Gateway 2010 Service Pack 3
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
For more information about how to implement cross-site single sign-on and trunk session time-out values, go to the following Microsoft TechNet websites: