AppLocker

AppLocker is an application whitelisting technology introduced with Microsoft's Windows 7 operating system. It allows restricting which programs users can execute based on the program's path, publisher, or hash,^[1] and in an enterprise can be configured via Group Policy.

Summary

Windows AppLocker allows administrators to control which executable files are denied or allowed to execute. With AppLocker, administrators are able to create rules based on file names, publishers or file location that will allow certain files to execute. Unlike the earlier Software Restriction Policies, which was originally available for Windows XP and Windows Server 2003,^[2] AppLocker rules can apply to individuals or groups. Policies are used to group users into different enforcement levels. For example, some users can be added to an 'audit' policy that will allow administrators to see the rule violations before moving that user to a higher enforcement level.

AppLocker availability charts

AppLocker availability on Windows 7^[3]

Starter	Home Basic	Home Premium	Professional	Enterprise	Ultimate
No	No	No	Create policies, but cannot enforce	Create and enforce policies	Create and enforce policies

AppLocker availability on Windows 8^[4]

RT	(Core)	Pro	Enterprise
No	No	No	Yes

AppLocker availability on Windows 10^[5][6][7]

Home	Pro	Enterprise	Education
Yes	Yes	Yes	Yes

Bypass techniques

There are several generic techniques for bypassing AppLocker:

• Writing an unapproved program to a whitelisted location.
• Using a whitelisted program as a delegate to launch an unapproved program.^{[8][9][10][11]}
• Hijacking the DLLs loaded by a trusted application in an untrusted directory.^[12]

References

1. "AppLocker". Microsoft TechNet. Microsoft. Retrieved 23 August 2012.
2. "Using Software Restriction Policies to Protect Against Unauthorized Software". Microsoft TechNet. Microsoft. Retrieved 27 July 2017.
3. "Windows Versions That Support AppLocker". Microsoft. Retrieved 27 July 2017.
4. Visser, Erwin (18 April 2012). "Introducing Windows 8 Enterprise and Enhanced Software Assurance for Today's Modern Workforce". Windows for your Business. Microsoft. Retrieved 22 November 2012.
5. Dudau, Vlad (10 June 2015). "Microsoft shows OEMs how to market Windows 10; talks features and SKUs". Neowin. Neowin LLC. Retrieved 19 June 2015.
6. "Find out which Windows is right for you". Microsoft. Microsoft Inc. Retrieved 2 July 2015.
7. "Removal of Windows edition checks for AppLocker". Microsoft. Microsoft Inc. Retrieved 22 February 2023.
8. "AppLocker Bypass – InstallUtil". Penetration Testing Lab. Retrieved 27 July 2017.
9. "AppLocker Bypass Techniques". Evi1cg's blog. Retrieved 27 July 2017.
10. "How to Bypass Windows AppLocker". Hacking Tutorial. Retrieved 27 July 2017.
11. "caseysmithrc/gethelp.cs". Github Gist. Retrieved 14 May 2019.
12. "Bypassing Application Whitelisting". CERT/CC Blog. Retrieved 27 July 2017.