Windows AMSI Related Registry Tampering Via CommandLine

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About the rule

Rule Type

Standard

Rule Description

Detects tampering of AMSI (Anti-Malware Scan Interface) related registry values via command line tools such as reg.exe or PowerShell.

Severity

Trouble

Rule Requirement

Criteria

Action1: actionname = "Process started" AND (( COMMANDLINE contains "\Software\Microsoft\Windows Script\Settings" AND COMMANDLINE contains "AmsiEnable" ) AND ((( PROCESSNAME endswith "\reg.exe" OR ORIGINALFILENAME = "reg.exe" ) AND COMMANDLINE contains "add" ) OR (( PROCESSNAME endswith "\powershell.exe,\pwsh.exe,\powershell_ise.exe" OR ORIGINALFILENAME = "PowerShell.EXE,pwsh.dll,powershell_ise.exe" ) AND COMMANDLINE contains "Set-ItemProperty,New-ItemProperty,sp " ))) select Action1.HOSTNAME,Action1.MESSAGE,Action1.COMMANDLINE,Action1.FILE_NAME,Action1.PROCESSNAME,Action1.USERNAME,Action1.PARENTPROCESSNAME,Action1.DOMAIN,Action1.ORIGINALFILENAME,Action1.PARENTPROCESSID,Action1.PROCESSID,Action1.PRODUCT_NAME,Action1.SECURITYID

Detection

Execution Mode

realtime

Log Sources

Windows

Author

@Swachchhanda Shrawan Poudel (Nextron Systems)