Windows reg.exe Adds or Modifies Suspicious Registry Locations via Command Line

Alerts on reg.exe registry modifications targeting specific Windows policy, security, Defender, and credential-related paths.

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windows-reg-exe-adds-or-modifies-suspicious-registry-locations-via-command-line-b7e2a8d4

title: Windows reg.exe Adds or Modifies Suspicious Registry Locations via Command Line
id: 8e10bcb1-de8b-4539-baef-ae133b00fcbb
status: test
description: This rule flags process creations where the Image ends with reg.exe (or OriginalFileName is reg.exe) and the command line contains paths associated with persistence, policy, or security-relevant registry areas. Attackers often use reg.exe to alter registry keys because it is a trusted Windows utility and can change system or security behavior without dropping custom binaries. The detection relies on Windows process creation telemetry, matching the executable name and specific substrings within the command line.
references:
  - https://github.com/redcanaryco/atomic-red-team/blob/40b77d63808dd4f4eafb83949805636735a1fd15/atomics/T1112/T1112.md
  - https://github.com/redcanaryco/atomic-red-team/blob/40b77d63808dd4f4eafb83949805636735a1fd15/atomics/T1562.001/T1562.001.md
  - https://www.absolomb.com/2018-01-26-Windows-Privilege-Escalation-Guide/
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/process_creation/proc_creation_win_reg_susp_paths.yml
author: frack113, Nasreddine Bencherchali (Nextron Systems), Huntrule Team
date: 2022-08-19
modified: 2022-10-10
tags:
  - attack.persistence
  - attack.defense-impairment
  - attack.t1112
  - attack.t1685
logsource:
  category: process_creation
  product: windows
detection:
  selection_reg:
    - Image|endswith: \reg.exe
    - OriginalFileName: reg.exe
  selection_path:
    CommandLine|contains:
      - \AppDataLow\Software\Microsoft\
      - \Policies\Microsoft\Windows\OOBE
      - \Policies\Microsoft\Windows NT\CurrentVersion\Winlogon
      - \SOFTWARE\Microsoft\Windows NT\Currentversion\Winlogon
      - \CurrentControlSet\Control\SecurityProviders\WDigest
      - \Microsoft\Windows Defender\
  condition: all of selection_*
falsepositives:
  - Rare legitimate add to registry via cli (to these locations)
level: high
license: DRL-1.1
related:
  - id: b7e2a8d4-74bb-4b78-adc9-3f92af2d4829
    type: derived

What it detects

This rule flags process creations where the Image ends with reg.exe (or OriginalFileName is reg.exe) and the command line contains paths associated with persistence, policy, or security-relevant registry areas. Attackers often use reg.exe to alter registry keys because it is a trusted Windows utility and can change system or security behavior without dropping custom binaries. The detection relies on Windows process creation telemetry, matching the executable name and specific substrings within the command line.

Known false positives

Rare legitimate add to registry via cli (to these locations)

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