SafeBoot Registry Key Deleted Via Reg.EXE — Sigma Rule

Rule metadata and linked tags

Author: Nasreddine Bencherchali (Nextron Systems), Tim Shelton. Source status: test; severity: high. Source dates: 2022-08-08 / 2023-02-04.

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

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 1d09d9cd03cd4fa369f105dd59624f86860a7987bfb98e3d55c6b6d7909858a7

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: SafeBoot Registry Key Deleted Via Reg.EXE
id: fc0e89b5-adb0-43c1-b749-c12a10ec37de
related:
    - id: d7662ff6-9e97-4596-a61d-9839e32dee8d
      type: similar
status: test
description: Detects execution of "reg.exe" commands with the "delete" flag on safe boot registry keys. Often used by attacker to prevent safeboot execution of security products
references:
    - https://www.trendmicro.com/en_us/research/22/e/avoslocker-ransomware-variant-abuses-driver-file-to-disable-anti-Virus-scans-log4shell.html
author: Nasreddine Bencherchali (Nextron Systems), Tim Shelton
date: 2022-08-08
modified: 2023-02-04
tags:
    - attack.defense-impairment
    - attack.t1685
logsource:
    category: process_creation
    product: windows
detection:
    selection_img:
        - Image|endswith: 'reg.exe'
        - OriginalFileName: 'reg.exe'
    selection_delete:
        CommandLine|contains|all:
            - ' delete '
            - '\SYSTEM\CurrentControlSet\Control\SafeBoot'
    condition: all of selection_*
falsepositives:
    - Unlikely
level: high

Original YAML and metadata in JSON

False positives

• Unlikely

Source references

• https://www.trendmicro.com/en_us/research/22/e/avoslocker-ransomware-variant-abuses-driver-file-to-disable-anti-Virus-scans-log4shell.html