Potential Commandline Obfuscation Using Escape Characters — Sigma Rule

Rule metadata and linked tags

Author: juju4. Source status: test; severity: medium. Source dates: 2018-12-11 / 2023-03-03.

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

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 8347931609c5bd886bc050b2a2ed61b73515d62591f42f2d1a2b8327deb94b07

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: Potential Commandline Obfuscation Using Escape Characters
id: f0cdd048-82dc-4f7a-8a7a-b87a52b6d0fd
status: test
description: Detects potential commandline obfuscation using known escape characters
references:
    - https://twitter.com/vysecurity/status/885545634958385153
    - https://twitter.com/Hexacorn/status/885553465417756673 # Dead link
    - https://twitter.com/Hexacorn/status/885570278637678592 # Dead link
    - https://www.mandiant.com/resources/blog/obfuscation-wild-targeted-attackers-lead-way-evasion-techniques
    - https://web.archive.org/web/20190213114956/http://www.windowsinspired.com/understanding-the-command-line-string-and-arguments-received-by-a-windows-program/
author: juju4
date: 2018-12-11
modified: 2023-03-03
tags:
    - attack.stealth
    - attack.t1140
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        CommandLine|contains:
            # - <TAB>   # no TAB modifier in sigmac yet, so this matches <TAB> (or TAB in elasticsearch backends without DSL queries)
            - 'h^t^t^p'
            - 'h"t"t"p'
    condition: selection
falsepositives:
    - Unknown
level: medium

Original YAML and metadata in JSON

False positives

• Unknown

Source references

• https://twitter.com/vysecurity/status/885545634958385153
• https://twitter.com/Hexacorn/status/885553465417756673
• https://twitter.com/Hexacorn/status/885570278637678592
• https://www.mandiant.com/resources/blog/obfuscation-wild-targeted-attackers-lead-way-evasion-techniques
• https://web.archive.org/web/20190213114956/http://www.windowsinspired.com/understanding-the-command-line-string-and-arguments-received-by-a-windows-program/