Suspicious Reg Add BitLocker — Sigma Rule

Rule metadata and linked tags

Author: frack113. Source status: test; severity: high. Source dates: 2021-11-15 / 2022-09-09.

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

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 58de8780d05bf4bd5f9e1082115a851231c44956a256138c43c2cc063bdfea82

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 Reg Add BitLocker
id: 0e0255bf-2548-47b8-9582-c0955c9283f5
status: test
description: Detects suspicious addition to BitLocker related registry keys via the reg.exe utility
references:
    - https://thedfirreport.com/2021/11/15/exchange-exploit-leads-to-domain-wide-ransomware/
author: frack113
date: 2021-11-15
modified: 2022-09-09
tags:
    - attack.impact
    - attack.t1486
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        CommandLine|contains|all:
            - 'REG'
            - 'ADD'
            - '\SOFTWARE\Policies\Microsoft\FVE'
            - '/v'
            - '/f'
        CommandLine|contains:
            - 'EnableBDEWithNoTPM'
            - 'UseAdvancedStartup'
            - 'UseTPM'
            - 'UseTPMKey'
            - 'UseTPMKeyPIN'
            - 'RecoveryKeyMessageSource'
            - 'UseTPMPIN'
            - 'RecoveryKeyMessage'
    condition: selection
falsepositives:
    - Unlikely
level: high

Original YAML and metadata in JSON

False positives

• Unlikely

Source references

• https://thedfirreport.com/2021/11/15/exchange-exploit-leads-to-domain-wide-ransomware/