Microsoft Defender Antivirus
TMA-DEFENDER-1.6.1.5
Ensure 'Configure Attack Surface Reduction rules: Set the state for each ASR rule' is set to '9e6c4e1f-7d60-472f-ba1a- a39ef669e4b2:1'
Description
This rule helps prevent credential stealing by locking down Local Security Authority Subsystem Service (LSASS). Rule ID and name: - 9e6c4e1f-7d60-472f-ba1a-a39ef669e4b2 (Block credential stealing from the Windows local security authority subsystem (lsass.exe)) The recommended state for this setting is: 9e6c4e1f-7d60-472f-ba1a- a39ef669e4b2:1 (Block). Rationale: Attack surface reduction helps prevent actions and apps that are typically used by exploit-seeking malware to infect machines. LSASS authenticates users who sign in on a Windows computer. Microsoft Defender Credential Guard in Windows normally prevents attempts to extract credentials from LSASS. Audit reads the Group Policy registry value and prints 'compliant', 'unset' (policy not configured, reported as FAIL) or the non-compliant value. Registry value: HKLM\SOFTWARE\Policies\Microsoft\Windows Defender\Windows Defender Exploit Guard\ASR\Rules:9e6c4e1f-7d60-472f-ba1a-a39ef669e4b2 (REG_SZ); compliant when it is 1.
How it is checked
Audit method: Windows registry
$v = (Get-ItemProperty -Path 'Registry::HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows Defender\Windows Defender Exploit Guard\ASR\Rules' -Name '9e6c4e1f-7d60-472f-ba1a-a39ef669e4b2' -ErrorAction SilentlyContinue).'9e6c4e1f-7d60-472f-ba1a-a39ef669e4b2'; if ($null -eq $v) { 'unset' } elseif (($null -ne $v -and @('1') -contains "$v")) { 'compliant' } else { "non-compliant: $v" }- Expected output
compliant
How it is fixed
Fix method: Guidance or infrastructure patch
Configure through Group Policy: Computer Configuration\Policies\Administrative Templates\Windows Components\Microsoft Defender Antivirus\Microsoft Defender Exploit Guard\Attack Surface Reduction\Configure Attack Surface Reduction rules: Set the state for each ASR rule = 9e6c4e1f-7d60-472f-ba1a-a39ef669e4b2 with a value of 1. Test in audit mode (2) first. Local alternative (writes Defender preferences, not the Group Policy value this audit reads): Add-MpPreference -AttackSurfaceReductionRules_Ids 9e6c4e1f-7d60-472f-ba1a-a39ef669e4b2 -AttackSurfaceReductionRules_Actions 1
Properties
- Operating systems
- Any
- Tags
- defenderantiviruscis-l1
- Reference
- CIS Microsoft Defender Antivirus Benchmark v1.0.0 - 1.6.1.5 Ensure 'Configure Attack Surface Reduction rules: Set the state for each ASR rule' is set to '9e6c4e1f-7d60-472f-ba1a- a39ef669e4b2:1'
Check this host
Run this on a machine you are allowed to audit. The scan is read-only.
tmaegis scan --target defender