The Microsoft Antimalware Client in Windows Defender on Windows 8 and Windows RT uses an incorrect pathname for MsMpEng.exe, which allows local users to gain privileges via a crafted application, aka "Microsoft Antimalware Improper Pathname Vulnerability."
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A16293
https://docs.microsoft.com/en-us/security-updates/securitybulletins/2013/ms13-034