Suspicious Mshta.EXE Execution Patterns — Sigma Rule

Rule metadata and linked tags

Author: Florian Roth (Nextron Systems), Nasreddine Bencherchali (Nextron Systems). Source status: test; severity: high. Source dates: 2021-07-17 / 2023-02-21.

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

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: cbae50ef58ad72a5f1c675f5cf64cab9453b81337a424282287cdf077b611ba7

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.EXE Execution Patterns
id: e32f92d1-523e-49c3-9374-bdb13b46a3ba
status: test
description: Detects suspicious mshta process execution patterns
references:
    - https://en.wikipedia.org/wiki/HTML_Application
    - https://www.echotrail.io/insights/search/mshta.exe
    - https://app.any.run/tasks/34221348-072d-4b70-93f3-aa71f6ebecad/
author: Florian Roth (Nextron Systems), Nasreddine Bencherchali (Nextron Systems)
date: 2021-07-17
modified: 2023-02-21
tags:
    - attack.execution
    - attack.t1106
logsource:
    category: process_creation
    product: windows
detection:
    selection_img:
        - Image|endswith: '\mshta.exe'
        - OriginalFileName: 'MSHTA.EXE'
    selection_susp:
        # Suspicious parents
        ParentImage|endswith:
            - '\cmd.exe'
            - '\cscript.exe'
            - '\powershell.exe'
            - '\pwsh.exe'
            - '\regsvr32.exe'
            - '\rundll32.exe'
            - '\wscript.exe'
        # Suspicious folders
        CommandLine|contains:
            - '\AppData\Local\'
            - 'C:\ProgramData\'
            - 'C:\Users\Public\'
            - 'C:\Windows\Temp\'
    filter_img:
        # Filter legit Locations
        - Image|startswith:
              - 'C:\Windows\System32\'
              - 'C:\Windows\SysWOW64\'
        # Suspicious extensions
        - CommandLine|contains:
              - '.htm'
              - '.hta'
        # Filter simple execution
        - CommandLine|endswith:
              - 'mshta.exe'
              - 'mshta'
    condition: all of selection_* or (selection_img and not filter_img)
falsepositives:
    - Unknown
level: high

Original YAML and metadata in JSON

False positives

• Unknown

Source references

• https://en.wikipedia.org/wiki/HTML_Application
• https://www.echotrail.io/insights/search/mshta.exe
• https://app.any.run/tasks/34221348-072d-4b70-93f3-aa71f6ebecad/