Potentially Suspicious Child Process Of WinRAR.EXE — Sigma Rule

Rule metadata and linked tags

Author: Nasreddine Bencherchali (Nextron Systems). Source status: test; severity: medium. Source dates: 2023-08-31 / not supplied.

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

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 8a4fe6f4ee1425583740e8269f39b07fd793fd84ccb3dd17dae753894536ab32

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: Potentially Suspicious Child Process Of WinRAR.EXE
id: 146aace8-9bd6-42ba-be7a-0070d8027b76
related:
    - id: ec3a3c2f-9bb0-4a9b-8f4b-5ec386544343
      type: similar
status: test
description: Detects potentially suspicious child processes of WinRAR.exe.
references:
    - https://www.group-ib.com/blog/cve-2023-38831-winrar-zero-day/
    - https://github.com/knight0x07/WinRAR-Code-Execution-Vulnerability-CVE-2023-38831/blob/26ab6c40b6d2c09bb4fc60feaa4a3a90cfd20c23/Part-1-Overview.md
author: Nasreddine Bencherchali (Nextron Systems)
date: 2023-08-31
tags:
    - attack.execution
    - attack.t1203
logsource:
    category: process_creation
    product: windows
detection:
    selection_parent:
        ParentImage|endswith: '\WinRAR.exe'
    selection_binaries:
        # Note: add additional binaries that the attacker might use
        - Image|endswith:
              - '\cmd.exe'
              - '\cscript.exe'
              - '\mshta.exe'
              - '\powershell.exe'
              - '\pwsh.exe'
              - '\regsvr32.exe'
              - '\rundll32.exe'
              - '\wscript.exe'
        - OriginalFileName:
              - 'Cmd.Exe'
              - 'cscript.exe'
              - 'mshta.exe'
              - 'PowerShell.EXE'
              - 'pwsh.dll'
              - 'regsvr32.exe'
              - 'RUNDLL32.EXE'
              - 'wscript.exe'
    condition: all of selection_*
falsepositives:
    - Unknown
level: medium

Original YAML and metadata in JSON

False positives

• Unknown

Source references

• https://www.group-ib.com/blog/cve-2023-38831-winrar-zero-day/
• https://github.com/knight0x07/WinRAR-Code-Execution-Vulnerability-CVE-2023-38831/blob/26ab6c40b6d2c09bb4fc60feaa4a3a90cfd20c23/Part-1-Overview.md