Suspicious Shim Database Patching Activity

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About the rule

Rule Type

Standard

Rule Description

Detects installation of new shim databases that try to patch sections of known processes for potential process injection or persistence.

Severity

Trouble

Rule Requirement

Criteria

Action1: actionname = "Registry value modified" AND (OBJECTNAME contains "\SOFTWARE\Microsoft\Windows NT\CurrentVersion\AppCompatFlags\Custom" OR (OBJECTNAME endswith "\SOFTWARE\Microsoft\Windows NT\CurrentVersion\AppCompatFlags\Custom" AND isExist(OBJECTVALUENAME))) AND OBJECTNAME endswith "\csrss.exe,\dllhost.exe,\explorer.exe,\RuntimeBroker.exe,\services.exe,\sihost.exe,\svchost.exe,\taskhostw.exe,\winlogon.exe,\WmiPrvSe.exe" select Action1.HOSTNAME,Action1.MESSAGE,Action1.OBJECTNAME,Action1.PROCESSNAME,Action1.PREVVAL,Action1.CHANGES

Detection

Execution Mode

realtime

Log Sources

Windows

Author

Nasreddine Bencherchali (Nextron Systems)