Regsvr32 DLL Execution With Suspicious File Extension

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About the rule

Rule Type

Standard

Rule Description

Detects the execution of REGSVR32.exe with DLL files masquerading as other files

Severity

Trouble

Rule Requirement

Criteria

Action1: actionname = "Process started" AND (PROCESSNAME endswith "\regsvr32.exe" OR ORIGINALFILENAME = "REGSVR32.EXE") AND COMMANDLINE endswith ".bin,.bmp,.cr2,.dat,.eps,.gif,.ico,.jpeg,.jpg,.nef,.orf,.png,.raw,.sr2,.temp,.tif,.tiff,.tmp,.rtf,.txt" select Action1.HOSTNAME,Action1.MESSAGE,Action1.COMMANDLINE,Action1.FILE_NAME,Action1.PROCESSNAME,Action1.USERNAME,Action1.PARENTPROCESSNAME

Detection

Execution Mode

realtime

Log Sources

Windows

Author

Florian Roth (Nextron Systems), frack113