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AppLocker is a powerful Windows 11 feature that helps control which apps and scripts users can run.

However, attackers often try to bypass AppLocker protections to run unauthorized programs.

Fixing these bypass exploits is crucial to keep your system secure and prevent malware infections.

This guide will walk you through simple and effective steps to stop AppLocker bypasses on Windows 11.

Quick Note Before You Begin

Before diving into fixes, ensure your Windows 11 is up to date. Microsoft regularly releases patches that improve AppLocker’s security.

Also, make sure you have administrative rights on your PC because you will need them to change AppLocker policies.

Finally, back up your current AppLocker policies. This helps you restore settings if something goes wrong.

Step 1: Review and Strengthen Your AppLocker Rules

The first step is to carefully check your existing AppLocker rules. Weak rules or overly broad exceptions often allow bypasses.

• Open Local Security Policy: Press Win + R, type secpol.msc, and hit Enter.
• Navigate to: Application Control Policies > AppLocker.
• Check each rule type: Executable rules, Windows Installer rules, Script rules, and Packaged app rules.
• Look for “Allow” rules that are too general: For example, rules allowing all apps from certain folders can be risky.

Why this matters: Tightening rules reduces the chances that malicious scripts or programs slip through by exploiting loose permissions.

Step 2: Enable Advanced Rule Enforcement

Windows 11 allows you to configure AppLocker to enforce rules strictly.

• In the AppLocker section, right-click on each rule collection (Executables, Scripts, etc.) and select Properties.
• Set the enforcement mode to Enforce rules instead of Audit only. This makes AppLocker actively block unauthorized apps.

Why this is important: Audit mode only logs violations but doesn’t block them, so attackers can still run forbidden apps.

Step 3: Block Known Bypass Tools and Techniques

Many bypass methods use legitimate Windows tools (like PowerShell or Regsvr32) in unintended ways.

• Create specific deny rules for known bypass tools that you do not need to run on your system.
• Use Publisher rules to allow only trusted signed applications.
• Consider restricting script hosts like powershell.exe and cscript.exe unless absolutely necessary.

Why this helps: Attackers often misuse legitimate system tools to evade detection. Blocking or restricting these limits their options.

Step 4: Use Windows Defender Application Control (WDAC) for Advanced Protection

If AppLocker alone is insufficient, you can enable WDAC, a more robust control system that works alongside AppLocker.

• WDAC uses policies to allow or deny apps at a deeper system level.
• Creating WDAC policies can be done via PowerShell or Group Policy.
• This option is recommended for enterprises or advanced users who need stronger controls.

Note: WDAC setup is more complex but offers better protection against sophisticated bypasses.

Step 5: Regularly Monitor AppLocker Logs

Monitoring helps you spot attempted bypasses early.

• Open Event Viewer by pressing Win + R, typing eventvwr.msc, and pressing Enter.
• Navigate to Applications and Services Logs > Microsoft > Windows > AppLocker > EXE and DLL.
• Review warnings and errors indicating blocked or attempted bypass activities.

Why monitoring matters: Frequent attempts to bypass AppLocker may signal a targeted attack or misconfigured rules.

FAQs

What is the most common way attackers bypass AppLocker?

Attackers often use trusted Windows tools like PowerShell, regsvr32, or mshta to run malicious code without triggering AppLocker.

Can I completely prevent all AppLocker bypasses?

No security measure is perfect, but combining strict AppLocker rules with WDAC and regular monitoring can minimize risks significantly.

Do I need to disable all scripting to secure AppLocker?

Not necessarily. Restricting scripting hosts to only trusted users and scripts is usually sufficient. Disabling them entirely can disrupt legitimate work.

Will enabling AppLocker slow down my system?

AppLocker runs efficiently in the background with minimal performance impact, so you should not notice any slowdowns.

Is AppLocker available on all editions of Windows 11?

AppLocker is available on Windows 11 Pro, Enterprise, and Education editions but not on the Home edition.

When Nothing Works

If you continue to experience AppLocker bypass exploits after following these steps, consider the following:

• Consult the official Microsoft documentation on AppLocker and WDAC for advanced troubleshooting: Microsoft AppLocker Docs.
• Engage IT security professionals to perform a detailed security audit.
• Consider upgrading to Windows 11 Enterprise for access to additional security features.
• Use endpoint protection solutions with behavior-based detection to complement AppLocker.

Conclusion

Fixing AppLocker bypass exploits on Windows 11 is essential for maintaining strong application control and system security.

Start by tightening your AppLocker rules, enforcing policies, and blocking known bypass tools.

For advanced protection, consider integrating Windows Defender Application Control and keep an eye on AppLocker logs regularly.

By following these step-by-step solutions, you can greatly reduce the risk of unauthorized apps running on your PC and keep your Windows 11 environment safer.