Suspicious HH.EXE Execution — Sigma Rule

Rule metadata and linked tags

Author: Maxim Pavlunin. 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: f231c06adee451e0d209b7cbc603fbd8cabc0265f0323fbd9d2d34eafa37dcb6

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 HH.EXE Execution
id: e8a95b5e-c891-46e2-b33a-93937d3abc31
status: test
description: Detects a suspicious execution 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
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_img:
        - OriginalFileName: 'HH.exe'
        - Image|endswith: '\hh.exe'
    selection_paths:
        CommandLine|contains:
            - '.application'
            - '\AppData\Local\Temp\'
            - '\Content.Outlook\'
            - '\Downloads\'
            - '\Users\Public\'
            - '\Windows\Temp\'
            # - '\AppData\Local\Temp\Temp?_'
            # - '\AppData\Local\Temp\Rar$'
            # - '\AppData\Local\Temp\7z'
            # - '\AppData\Local\Temp\wz'
            # - '\AppData\Local\Temp\peazip-tmp'
    condition: all of 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