Suspicious Svchost Process Access — Sigma Rule

Rule metadata and linked tags

Author: Tim Burrell. Source status: test; severity: high. Source dates: 2020-01-02 / 2023-01-30.

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

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 033b8ee19d35b6a48c9d2c6a0e3c6b8a026d6a92a012efb598d8d009eb7b28e2

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 Svchost Process Access
id: 166e9c50-8cd9-44af-815d-d1f0c0e90dde
status: test
description: Detects suspicious access to the "svchost" process such as that used by Invoke-Phantom to kill the thread of the Windows event logging service.
references:
    - https://github.com/hlldz/Invoke-Phant0m
    - https://twitter.com/timbmsft/status/900724491076214784
author: Tim Burrell
date: 2020-01-02
modified: 2023-01-30
tags:
    - attack.defense-impairment
    - attack.t1685.001
logsource:
    category: process_access
    product: windows
detection:
    selection:
        TargetImage|endswith: ':\Windows\System32\svchost.exe'
        GrantedAccess: '0x1F3FFF'
        CallTrace|contains: 'UNKNOWN'
    filter_main_msbuild:
        SourceImage|contains: ':\Program Files\Microsoft Visual Studio\'
        SourceImage|endswith: '\MSBuild\Current\Bin\MSBuild.exe'
        # Just to make sure it's "really" .NET :)
        CallTrace|contains:
            - 'Microsoft.Build.ni.dll'
            - 'System.ni.dll'
    condition: selection and not 1 of filter_main_*
falsepositives:
    - Unknown
level: high

Original YAML and metadata in JSON

False positives

• Unknown

Source references

• https://github.com/hlldz/Invoke-Phant0m
• https://twitter.com/timbmsft/status/900724491076214784