The computer clock synchronization tolerance must be limited to 5 minutes or less.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-2380	WN12-AC-000014-DC	SV-51168r1_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
Windows Server 2012 / 2012 R2 Domain Controller Security Technical Implementation Guide	2014-06-30

Details

Check Text ( C-46594r1_chk )
Verify the following is configured in the Default Domain Policy. Open "Group Policy Management". Navigate to "Group Policy Objects" in the Domain being reviewed (Forest > Domains > Domain). Right click on the "Default Domain Policy". Select Edit. Navigate to Computer Configuration > Policies > Windows Settings > Security Settings > Account Policies > Kerberos Policy. If the "Maximum tolerance for computer clock synchronization" is greater than 5 minutes, this is a finding.

Check Text ( C-46594r1_chk )

Verify the following is configured in the Default Domain Policy.

Open "Group Policy Management".
Navigate to "Group Policy Objects" in the Domain being reviewed (Forest > Domains > Domain).
Right click on the "Default Domain Policy".
Select Edit.
Navigate to Computer Configuration > Policies > Windows Settings > Security Settings > Account Policies > Kerberos Policy.

If the "Maximum tolerance for computer clock synchronization" is greater than 5 minutes, this is a finding.

Fix Text (F-44325r1_fix)
Configure the policy value in the Default Domain Policy for Computer Configuration -> Windows Settings -> Security Settings -> Account Policies -> Kerberos Policy -> "Maximum tolerance for computer clock synchronization" to a maximum of 5 minutes or less.