Understanding WDAC and Script Enforcement for Enhanced Security

Windows Defender Application Control (WDAC) is a powerful feature that allows organizations to control which applications and scripts can run on their systems. While many are aware of its capabilities for executable files, WDAC also includes Script Enforcement, which extends its protection to scripts like PowerShell, JavaScript, and VBScript. This feature is crucial for reducing the attack surface and mitigating risks associated with malicious script execution.

You Should Know:

1. Enabling WDAC Script Enforcement:

To enable WDAC Script Enforcement, you need to configure a WDAC policy. Here’s how you can do it:

<h1>Create a new WDAC policy</h1>

New-CIPolicy -FilePath "C:\WDAC\Policy.xml" -Level FilePublisher -Fallback SignedVersion,Hash -UserPEs

<h1>Enable Script Enforcement in the policy</h1>

Set-RuleOption -FilePath "C:\WDAC\Policy.xml" -Option 3

<h1>Deploy the WDAC policy</h1>

ConvertFrom-CIPolicy -XmlFilePath "C:\WDAC\Policy.xml" -BinaryFilePath "C:\WDAC\Policy.bin"

2. Blocking Malicious Scripts:

WDAC can block scripts from untrusted sources. For example, to block a specific PowerShell script:

<h1>Add a rule to block a specific script hash</h1>

Add-SignerRule -FilePath "C:\WDAC\Policy.xml" -CertificatePath "C:\Path\To\Certificate.cer" -KernelMode

3. Reducing LOLBins Abuse:

WDAC can prevent Living Off the Land Binaries (LOLBins) from executing unwanted scripts. For instance, to restrict wscript.exe:

<h1>Add a rule to restrict wscript.exe</h1>

Add-SignerRule -FilePath "C:\WDAC\Policy.xml" -FilePath "C:\Windows\System32\wscript.exe" -Deny

4. Auditing and Monitoring:

Use PowerShell to audit script execution attempts:

<h1>Enable script execution auditing</h1>

Set-MpPreference -EnableScriptScanning $true

5. Deploying WDAC Policies:

Deploy the WDAC policy across your environment using Group Policy or Intune:

<h1>Deploy WDAC policy via Group Policy</h1>

Copy-Item -Path "C:\WDAC\Policy.bin" -Destination "C:\Windows\System32\CodeIntegrity\SIPolicy.p7b"

What Undercode Say:

WDAC Script Enforcement is a critical tool for securing your environment against script-based attacks. By controlling which scripts can run, you can significantly reduce the risk of ransomware, post-exploitation activities, and other malicious behaviors. Implementing WDAC requires careful planning and testing, but the security benefits far outweigh the initial effort. For more detailed guidance, refer to the official Microsoft documentation on WDAC: WDAC Documentation.

Additional Commands for Enhanced Security:

• Linux:

  </li>
  </ul>
  
  <h1>Monitor script execution in real-time</h1>
  
  sudo auditctl -w /path/to/scripts -p wa -k script_monitor
  

  • Windows:

    </li>
    </ul>
    
    <h1>Check WDAC policy status</h1>
    
    Get-CIPolicy -FilePath "C:\WDAC\Policy.xml"
    

    • General IT Security:

      </li>
      </ul>
      
      <h1>Check for unauthorized changes in system files</h1>
      
      sudo tripwire --check
      

      By leveraging WDAC and Script Enforcement, you can create a more secure and controlled environment, minimizing the risk of script-based threats.

      References:

      Reported By: Spenceralessi Did – Hackers Feeds
      Extra Hub: Undercode MoN
      Basic Verification: Pass ✅

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