Cscript/Wscript Potentially Suspicious Child Process

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About the rule

Rule Type

Standard

Rule Description

Detects potentially suspicious child processes of Wscript/Cscript. These include processes such as rundll32 with uncommon exports or PowerShell spawning rundll32 or regsvr32. Malware such as Pikabot and Qakbot were seen using similar techniques as well as many others.

Severity

Trouble

Rule Requirement

Criteria

Action1: actionname = "Process started" AND PARENTPROCESSNAME endswith "\wscript.exe,\cscript.exe" AND (PROCESSNAME endswith "\rundll32.exe" OR (PROCESSNAME endswith "\cmd.exe,\powershell.exe,\pwsh.exe" AND ((COMMANDLINE contains "mshta" AND COMMANDLINE contains "http") OR COMMANDLINE contains "rundll32,regsvr32,msiexec"))) AND (PROCESSNAME notendswith "\rundll32.exe" OR COMMANDLINE notcontains "UpdatePerUserSystemParameters,PrintUIEntry,ClearMyTracksByProcess") select Action1.HOSTNAME,Action1.MESSAGE,Action1.COMMANDLINE,Action1.FILE_NAME,Action1.PROCESSNAME,Action1.USERNAME,Action1.PARENTPROCESSNAME

Detection

Execution Mode

realtime

Log Sources

Windows

Author

Nasreddine Bencherchali (Nextron Systems), Alejandro Houspanossian ('@lekz86')