Ensure 'Configure Attack Surface Reduction rules: Set the state for each ASR rule' is set to '5beb7efe-fd9a-4556-801d- 275e5ffc04cc:2' or higher

HighLevel 1Automateddefender

Description

This rule detects suspicious properties within an obfuscated script. Rule ID and name: - 5beb7efe-fd9a-4556-801d-275e5ffc04cc (Block execution of potentially obfuscated scripts) The recommended state for this setting is: 5beb7efe-fd9a-4556-801d- 275e5ffc04cc:2 (Audit). Configuring this setting to 5beb7efe-fd9a-4556-801d- 275e5ffc04cc:1 (Block) also conforms to the benchmark. Rationale: Attack surface reduction helps prevent actions and apps that are typically used by exploit-seeking malware to infect machines. Script obfuscation is a common technique that both malware authors and legitimate applications use to hide intellectual property or decrease script loading times. 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:5beb7efe-fd9a-4556-801d-275e5ffc04cc (REG_SZ); compliant when it is 2 or 1.

How it is checked

Audit method: Windows registry

registry

$v = (Get-ItemProperty -Path 'Registry::HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows Defender\Windows Defender Exploit Guard\ASR\Rules' -Name '5beb7efe-fd9a-4556-801d-275e5ffc04cc' -ErrorAction SilentlyContinue).'5beb7efe-fd9a-4556-801d-275e5ffc04cc'; if ($null -eq $v) { 'unset' } elseif (($null -ne $v -and @('2','1') -contains "$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 = 5beb7efe-fd9a-4556-801d-275e5ffc04cc with a value of 2 or 1. Test in audit mode (2) first. Local alternative (writes Defender preferences, not the Group Policy value this audit reads): Add-MpPreference -AttackSurfaceReductionRules_Ids 5beb7efe-fd9a-4556-801d-275e5ffc04cc -AttackSurfaceReductionRules_Actions 2

Properties

Operating systems: Any
Tags: defenderantiviruscis-l1
Reference: CIS Microsoft Defender Antivirus Benchmark v1.0.0 - 1.6.1.8 Ensure 'Configure Attack Surface Reduction rules: Set the state for each ASR rule' is set to '5beb7efe-fd9a-4556-801d- 275e5ffc04cc:2' or higher

Check this host

Run this on a machine you are allowed to audit. The scan is read-only.

shell

tmaegis scan --target defender