Suspicious MSHTA Child Process — Sigma Rule

Rule metadata and linked tags

Author: Michael Haag. Source status: test; severity: high. Source dates: 2019-01-16 / 2023-02-06.

{
  "category": "process_creation",
  "product": "windows"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 8a32fc6f6030da48f4e22446d7446ffb85b7801158ec204e4659a657ecc44380

Detection logic

Original source YAML. Source-tag agreement is not proof of complete semantic coverage. This rule has not been compiled for a SIEM backend or validated against live telemetry here.

title: Suspicious MSHTA Child Process
id: 03cc0c25-389f-4bf8-b48d-11878079f1ca
status: test
description: Detects a suspicious process spawning from an "mshta.exe" process, which could be indicative of a malicious HTA script execution
references:
    - https://www.trustedsec.com/july-2015/malicious-htas/
author: Michael Haag
date: 2019-01-16
modified: 2023-02-06
tags:
    - attack.stealth
    - attack.t1218.005
    - car.2013-02-003
    - car.2013-03-001
    - car.2014-04-003
logsource:
    category: process_creation
    product: windows
detection:
    selection_parent:
        ParentImage|endswith: '\mshta.exe'
    selection_child:
        - Image|endswith:
              - '\cmd.exe'
              - '\powershell.exe'
              - '\pwsh.exe'
              - '\wscript.exe'
              - '\cscript.exe'
              - '\sh.exe'
              - '\bash.exe'
              - '\reg.exe'
              - '\regsvr32.exe'
              - '\bitsadmin.exe'
        - OriginalFileName:
              - 'Cmd.Exe'
              - 'PowerShell.EXE'
              - 'pwsh.dll'
              - 'wscript.exe'
              - 'cscript.exe'
              - 'Bash.exe'
              - 'reg.exe'
              - 'REGSVR32.EXE'
              - 'bitsadmin.exe'
    condition: all of selection*
falsepositives:
    - Printer software / driver installations
    - HP software
level: high

Original YAML and metadata in JSON

False positives

• Printer software / driver installations
• HP software

Source references

• https://www.trustedsec.com/july-2015/malicious-htas/