TMA-INTUNE-DEFENDER-2.14
Ensure 'ASR: Block executable content from email client and webmail' is set to 'Block'
Description
This rule blocks email opened within the Microsoft Outlook application, or Outlook.com and other popular webmail providers from propagating the following file types: • Executable files (such as .exe, .dll, or .scr) • Script files (such as a PowerShell .ps1, Visual Basic .vbs, or JavaScript .js file) The recommended state for this setting is: Block. Audit: reads the Intune PolicyManager ASR rules value (via the WinningProvider GUID) and requires the rule entry be9ba2d9-53ea-4cdc-84e5-9b1eeee46550=1 (Block).
How it is checked
Audit method: Windows registry
$p = (Get-ItemProperty -Path 'Registry::HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\PolicyManager\current\device\Defender' -Name 'AttackSurfaceReductionRules_WinningProvider' -ErrorAction SilentlyContinue).'AttackSurfaceReductionRules_WinningProvider'; if (-not $p) { 'non-compliant: no ASR WinningProvider' } else { $p = ([string]$p).Trim('{}'); $k = 'Registry::HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\PolicyManager\Providers\' + $p + '\default\Device\Defender'; if (-not (Test-Path $k)) { $k = 'Registry::HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\PolicyManager\Providers\{' + $p + '}\default\Device\Defender' }; $v = (Get-ItemProperty -Path $k -Name 'AttackSurfaceReductionRules' -ErrorAction SilentlyContinue).'AttackSurfaceReductionRules'; $have = @(([string]$v) -split '\|' | ForEach-Object { $_.Trim().ToLower() }); $want = @('be9ba2d9-53ea-4cdc-84e5-9b1eeee46550=1'); if (@($want | Where-Object { $have -contains $_ }).Count -gt 0) { 'compliant' } else { 'non-compliant: ' + $v } }- Expected output
compliant
How it is fixed
Fix method: Guidance or infrastructure patch
To establish the recommended configuration via configuration profiles, set the following Settings Catalog path to Block. Defender\Block executable content from email client and webmail
Properties
- Operating systems
- Any
- Tags
- intune-defenderintuneregistry
- Reference
- CIS Microsoft Intune for Microsoft Defender Antivirus Benchmark v1.0.0 - 2.14 Ensure 'ASR: Block executable content from email client and webmail' is set to 'Block'
Check this host
Run this on a machine you are allowed to audit. The scan is read-only.
tmaegis scan --target intune-defender