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NTLM must be prevented from falling back to a Null session.


Overview

Finding ID Version Rule ID IA Controls Severity
WN12-SO-000062 WN12-SO-000062 WN12-SO-000062_rule Medium
Description
NTLM sessions that are allowed to fall back to Null (unauthenticated) sessions may gain unauthorized access.
STIG Date
Microsoft Windows Server 2012 Domain Controller Security Technical Implementation Guide 2013-07-25

Details

Check Text ( C-WN12-SO-000062_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\Control\LSA\MSV1_0\

Value Name: allownullsessionfallback

Type: REG_DWORD
Value: 0
Fix Text (F-WN12-SO-000062_fix)
Configure the policy value for Computer Configuration -> Windows Settings -> Security Settings -> Local Policies -> Security Options -> "Network security: Allow LocalSystem NULL session fallback" to "Disabled".