The Kerberos policy option "Maximum tolerance for computer clock synchronization" must be set to a maximum of 5 minutes or less.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-2380	AD.4033_2008	SV-28505r2_rule	ECSC-1	Medium

Description
This setting determines the maximum time difference (in minutes) that Kerberos will tolerate between the time on a client's clock and the time on a server's clock while still considering the two clocks synchronous. In order to prevent replay attacks, Kerberos uses timestamps as part of its protocol definition. For timestamps to work properly, the clocks of the client and the server need to be in sync as much as possible.

Description

This setting determines the maximum time difference (in minutes) that Kerberos will tolerate between the time on a client's clock and the time on a server's clock while still considering the two clocks synchronous. In order to prevent replay attacks, Kerberos uses timestamps as part of its protocol definition. For timestamps to work properly, the clocks of the client and the server need to be in sync as much as possible.

STIG	Date
Active Directory Service 2008 Security Technical Implementation Guide (STIG)	2011-05-23

Details

Check Text ( C-472r2_chk )
1. Analyze the system using the Security Configuration and Analysis tool. 2. Expand the Security Configuration and Analysis tree view. 3. Navigate to Account Policies -> Kerberos Policy. 4. If the “Maximum tolerance for computer clock synchronization” is greater than ‘5’ minutes, then this is a finding.

Fix Text (F-5785r2_fix)
Configure the Kerberos policy option Maximum tolerance for computer clock synchronization to a maximum of 5 minutes or less.