Windows Process Creation: Suspicious reg.exe Query for MachineGuid

Detects reg.exe queries for MachineGuid under SOFTWARE\Microsoft\Cryptography via process creation logs.

FreeUnreviewedSigmalowv1

windows-process-creation-suspicious-reg-exe-query-for-machineguid-f5240972

title: "Windows Process Creation: Suspicious reg.exe Query for MachineGuid"
id: 4535bdd2-2e8a-448d-a1fd-0c7a301e1097
status: test
description: This rule flags Windows process executions where reg.exe is used with command-line arguments that query the SOFTWARE\Microsoft\Cryptography registry location for the MachineGuid value. Attackers may use MachineGuid as a stable host identifier to support discovery, correlation, or environment fingerprinting. Detection relies on process creation telemetry including the executable path and full command line arguments.
references:
  - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1082/T1082.md#atomic-test-8---windows-machineguid-discovery
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/process_creation/proc_creation_win_reg_machineguid.yml
author: frack113, Huntrule Team
date: 2022-01-01
tags:
  - attack.discovery
  - attack.t1082
logsource:
  category: process_creation
  product: windows
detection:
  selection:
    Image|endswith: \reg.exe
    CommandLine|contains|all:
      - SOFTWARE\Microsoft\Cryptography
      - "/v "
      - MachineGuid
  condition: selection
falsepositives:
  - Unknown
level: low
license: DRL-1.1
related:
  - id: f5240972-3938-4e56-8e4b-e33893176c1f
    type: derived

What it detects

This rule flags Windows process executions where reg.exe is used with command-line arguments that query the SOFTWARE\Microsoft\Cryptography registry location for the MachineGuid value. Attackers may use MachineGuid as a stable host identifier to support discovery, correlation, or environment fingerprinting. Detection relies on process creation telemetry including the executable path and full command line arguments.

Known false positives

Unknown

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.