HTML Help HH.EXE Suspicious Child Process — Sigma Rule

Rule metadata and linked tags

Author: Maxim Pavlunin, Nasreddine Bencherchali (Nextron Systems). Source status: test; severity: high. Source dates: 2020-04-01 / 2023-04-12.

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

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 4cb721eccb6e2a63e399b6a54b687ddc739985dbcc0d525fa6f9fb534dd8cd72

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: HTML Help HH.EXE Suspicious Child Process
id: 52cad028-0ff0-4854-8f67-d25dfcbc78b4
status: test
description: Detects a suspicious child process of a Microsoft HTML Help (HH.exe)
references:
    - https://www.trustwave.com/en-us/resources/blogs/spiderlabs-blog/chm-badness-delivers-a-banking-trojan/
    - https://github.com/elastic/protections-artifacts/commit/746086721fd385d9f5c6647cada1788db4aea95f#diff-27939090904026cc396b0b629c8e4314acd6f5dac40a676edbc87f4567b47eb7
    - https://www.ptsecurity.com/ww-en/analytics/pt-esc-threat-intelligence/higaisa-or-winnti-apt-41-backdoors-old-and-new/
    - https://www.zscaler.com/blogs/security-research/unintentional-leak-glimpse-attack-vectors-apt37
author: Maxim Pavlunin, Nasreddine Bencherchali (Nextron Systems)
date: 2020-04-01
modified: 2023-04-12
tags:
    - attack.execution
    - attack.initial-access
    - attack.stealth
    - attack.t1047
    - attack.t1059.001
    - attack.t1059.003
    - attack.t1059.005
    - attack.t1059.007
    - attack.t1218
    - attack.t1218.001
    - attack.t1218.010
    - attack.t1218.011
    - attack.t1566
    - attack.t1566.001
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        ParentImage|endswith: '\hh.exe'
        Image|endswith:
            - '\CertReq.exe'
            - '\CertUtil.exe'
            - '\cmd.exe'
            - '\cscript.exe'
            - '\installutil.exe'
            - '\MSbuild.exe'
            - '\MSHTA.EXE'
            - '\msiexec.exe'
            - '\powershell.exe'
            - '\pwsh.exe'
            - '\regsvr32.exe'
            - '\rundll32.exe'
            - '\schtasks.exe'
            - '\wmic.exe'
            - '\wscript.exe'
    condition: selection
falsepositives:
    - Unknown
level: high

Original YAML and metadata in JSON

False positives

• Unknown

Source references

• https://www.trustwave.com/en-us/resources/blogs/spiderlabs-blog/chm-badness-delivers-a-banking-trojan/
• https://github.com/elastic/protections-artifacts/commit/746086721fd385d9f5c6647cada1788db4aea95f#diff-27939090904026cc396b0b629c8e4314acd6f5dac40a676edbc87f4567b47eb7
• https://www.ptsecurity.com/ww-en/analytics/pt-esc-threat-intelligence/higaisa-or-winnti-apt-41-backdoors-old-and-new/
• https://www.zscaler.com/blogs/security-research/unintentional-leak-glimpse-attack-vectors-apt37