Windows Server 2019 local administrator accounts must have their privileged token filtered to prevent elevated privileges from being used over the network on domain-joined member servers.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-93519	WN19-MS-000020	SV-103605r1_rule		Medium

Description
A compromised local administrator account can provide means for an attacker to move laterally between domain systems. With User Account Control enabled, filtering the privileged token for local administrator accounts will prevent the elevated privileges of these accounts from being used over the network.

STIG	Date
Windows Server 2019 Security Technical Implementation Guide	2019-07-09

Details

Check Text ( C-92835r1_chk )
This applies to member servers. For domain controllers and standalone systems, this is NA. 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: \SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System Value Name: LocalAccountTokenFilterPolicy Type: REG_DWORD Value: 0x00000000 (0) This setting may cause issues with some network scanning tools if local administrative accounts are used remotely. Scans should use domain accounts where possible. If a local administrative account must be used, temporarily enabling the privileged token by configuring the registry value to "1" may be required.

Check Text ( C-92835r1_chk )

This applies to member servers. For domain controllers and standalone systems, this is NA.

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: \SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System

Value Name: LocalAccountTokenFilterPolicy

Type: REG_DWORD
Value: 0x00000000 (0)

This setting may cause issues with some network scanning tools if local administrative accounts are used remotely. Scans should use domain accounts where possible. If a local administrative account must be used, temporarily enabling the privileged token by configuring the registry value to "1" may be required.

Fix Text (F-99763r1_fix)
Configure the policy value for Computer Configuration >> Administrative Templates >> MS Security Guide >> "Apply UAC restrictions to local accounts on network logons" to "Enabled". This policy setting requires the installation of the SecGuide custom templates included with the STIG package. "SecGuide.admx" and " SecGuide.adml" must be copied to the \Windows\PolicyDefinitions and \Windows\PolicyDefinitions\en-US directories respectively.

Fix Text (F-99763r1_fix)

Configure the policy value for Computer Configuration >> Administrative Templates >> MS Security Guide >> "Apply UAC restrictions to local accounts on network logons" to "Enabled".

This policy setting requires the installation of the SecGuide custom templates included with the STIG package. "SecGuide.admx" and " SecGuide.adml" must be copied to the \Windows\PolicyDefinitions and \Windows\PolicyDefinitions\en-US directories respectively.