IPSec Exemptions must be limited.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-14232	WN12-SO-000042	SV-52945r1_rule		Low

Description
IPSec exemption filters allow specific traffic that may be needed by the system for such things as Kerberos authentication. This setting configures Windows for specific IPSec exemptions.

STIG	Date
Windows Server 2012/2012 R2 Domain Controller Security Technical Implementation Guide	2020-06-16

Details

Check Text ( C-47251r2_chk )
If the following registry value does not exist or is not configured as specified, this is a finding: Registry Hive: HKEY_LOCAL_MACHINE Registry Path: \System\CurrentControlSet\Services\IPSEC\ Value Name: NoDefaultExempt Value Type: REG_DWORD Value: 3

Fix Text (F-45871r2_fix)
Configure the policy value for Computer Configuration -> Windows Settings -> Security Settings -> Local Policies -> Security Options -> "MSS: (NoDefaultExempt) Configure IPSec exemptions for various types of network traffic" to "Only ISAKMP is exempt (recommended for Windows Server 2003)". (See "Updating the Windows Security Options File" in the STIG Overview document if MSS settings are not visible in the system's policy tools.)

Fix Text (F-45871r2_fix)

Configure the policy value for Computer Configuration -> Windows Settings -> Security Settings -> Local Policies -> Security Options -> "MSS: (NoDefaultExempt) Configure IPSec exemptions for various types of network traffic" to "Only ISAKMP is exempt (recommended for Windows Server 2003)".

(See "Updating the Windows Security Options File" in the STIG Overview document if MSS settings are not visible in the system's policy tools.)