Unauthorized System Time Modification — Sigma Rule

Rule metadata and linked tags

Author: @neu5ron. Source status: test; severity: low. Source dates: 2019-02-05 / 2025-12-03.

{
  "product": "windows",
  "service": "security",
  "definition": "Requirements: Audit Policy : System > Audit Security State Change, Group Policy : Computer Configuration\\Windows Settings\\Security Settings\\Advanced Audit Policy Configuration\\Audit Policies\\System\\Audit Security State Change"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: e2caeb0b98e80fd21eb6bd31e7e67aa69eb6f11a8c0f4a4febeaa488c2bd4c37

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: Unauthorized System Time Modification
id: faa031b5-21ed-4e02-8881-2591f98d82ed
status: test
description: Detect scenarios where a potentially unauthorized application or user is modifying the system time.
references:
    - Private Cuckoo Sandbox (from many years ago, no longer have hash, NDA as well)
    - Live environment caused by malware
    - https://learn.microsoft.com/en-us/previous-versions/windows/it-pro/windows-10/security/threat-protection/auditing/event-4616
author: '@neu5ron'
date: 2019-02-05
modified: 2025-12-03
tags:
    - attack.stealth
    - attack.t1070.006
logsource:
    product: windows
    service: security
    definition: 'Requirements: Audit Policy : System > Audit Security State Change, Group Policy : Computer Configuration\Windows Settings\Security Settings\Advanced Audit Policy Configuration\Audit Policies\System\Audit Security State Change'
detection:
    selection:
        EventID: 4616
    filter_main_svchost:
        ProcessName: 'C:\Windows\System32\svchost.exe'
        SubjectUserSid: 'S-1-5-19'
    filter_optional_vmtools:
        ProcessName:
            - 'C:\Program Files\VMware\VMware Tools\vmtoolsd.exe'
            - 'C:\Program Files (x86)\VMware\VMware Tools\vmtoolsd.exe'
            - 'C:\Windows\System32\VBoxService.exe'
            - 'C:\Windows\System32\oobe\msoobe.exe'
    condition: selection and not 1 of filter_main_* and not 1 of filter_optional_*
falsepositives:
    - HyperV or other virtualization technologies with binary not listed in filter portion of detection
level: low

Original YAML and metadata in JSON

False positives

• HyperV or other virtualization technologies with binary not listed in filter portion of detection

Source references

• Private Cuckoo Sandbox (from many years ago, no longer have hash, NDA as well) (source note; no public URL supplied)
• Live environment caused by malware (source note; no public URL supplied)
• https://learn.microsoft.com/en-us/previous-versions/windows/it-pro/windows-10/security/threat-protection/auditing/event-4616