Potential Process Hollowing Activity — Sigma Rule

Rule metadata and linked tags

Author: Christopher Peacock '@securepeacock', SCYTHE '@scythe_io', Sittikorn S. Source status: test; severity: medium. Source dates: 2022-01-25 / 2023-11-28.

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

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 4b38bcd283a0445d82502d652dc1e5ceaa0ff5a31616cae5a60b9dee5f529397

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 Process Hollowing Activity
id: c4b890e5-8d8c-4496-8c66-c805753817cd
status: test
description: Detects when a memory process image does not match the disk image, indicative of process hollowing.
references:
    - https://twitter.com/SecurePeacock/status/1486054048390332423?s=20
    - https://www.bleepingcomputer.com/news/microsoft/microsoft-sysmon-now-detects-malware-process-tampering-attempts/
author: Christopher Peacock '@securepeacock', SCYTHE '@scythe_io', Sittikorn S
date: 2022-01-25
modified: 2023-11-28
tags:
    - attack.privilege-escalation
    - attack.stealth
    - attack.t1055.012
logsource:
    product: windows
    category: process_tampering
detection:
    selection:
        Type: 'Image is replaced'
    filter_main_generic:
        Image|contains:
            - ':\Program Files (x86)'
            - ':\Program Files\'
            - ':\Windows\System32\wbem\WMIADAP.exe'
            - ':\Windows\SysWOW64\wbem\WMIADAP.exe'
    filter_optional_opera:
        Image|contains: '\AppData\Local\Programs\Opera\'
        Image|endswith: '\opera.exe'
    filter_optional_edge:
        Image|endswith: '\WindowsApps\MicrosoftEdge.exe'
    condition: selection and not 1 of filter_main_* and not 1 of filter_optional_*
falsepositives:
    - Unknown
level: medium

Original YAML and metadata in JSON

False positives

• Unknown

Source references

• https://twitter.com/SecurePeacock/status/1486054048390332423?s=20
• https://www.bleepingcomputer.com/news/microsoft/microsoft-sysmon-now-detects-malware-process-tampering-attempts/