LoFP LoFP / some false positives might occur with admin or third party software scripts. investigate and apply additional filters accordingly.

Techniques

Sample rules

Cscript/Wscript Potentially Suspicious Child Process

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.

Detection logic

condition: selection_parent and ( selection_cli_standalone or (selection_cli_script_main
  and 1 of selection_cli_script_option_*) ) and not 1 of filter_main_*
filter_main_rundll32_known_exports:
  CommandLine|contains:
  - UpdatePerUserSystemParameters
  - PrintUIEntry
  - ClearMyTracksByProcess
  Image|endswith: \rundll32.exe
selection_cli_script_main:
  Image|endswith:
  - \cmd.exe
  - \powershell.exe
  - \pwsh.exe
selection_cli_script_option_mshta:
  CommandLine|contains|all:
  - mshta
  - http
selection_cli_script_option_other:
  CommandLine|contains:
  - rundll32
  - regsvr32
  - msiexec
selection_cli_standalone:
  Image|endswith: \rundll32.exe
selection_parent:
  ParentImage|endswith:
  - \wscript.exe
  - \cscript.exe