Windows: Suspicious Service Installation via Registry ImagePath Outside system32

title: "Windows: Suspicious Service Installation via Registry ImagePath Outside system32"
id: 3c4018e6-b289-4633-a105-f76e5080bad1
status: test
description: This rule flags registry changes indicating installation of NalDrv or PROCEXP152 Windows services where the configured ImagePath points outside the Windows\system32\Drivers\PROCEXP152.SYS location. Such service installation can be used by attackers to persist or load components from non-standard locations, potentially evading normal expectations for system binaries. It relies on registry set telemetry for service ImagePath values under HKLM\System\CurrentControlSet\Services\<service>.
references:
  - https://web.archive.org/web/20200419024230/https://blog.dylan.codes/evading-sysmon-and-windows-event-logging/
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/registry/registry_set/registry_set_susp_service_installed.yml
author: xknow (@xknow_infosec), xorxes (@xor_xes), Huntrule Team
date: 2019-04-08
modified: 2026-06-29
tags:
  - attack.defense-impairment
  - attack.t1685
logsource:
  category: registry_set
  product: windows
detection:
  selection:
    TargetObject:
      - HKLM\System\CurrentControlSet\Services\NalDrv\ImagePath
      - HKLM\System\CurrentControlSet\Services\PROCEXP152\ImagePath
  filter:
    Image|endswith:
      - \procexp64.exe
      - \procexp64a.exe
      - \procexp.exe
      - \procmon64.exe
      - \procmon64a.exe
      - \procmon.exe
      - \handle.exe
      - \handle64.exe
      - \handle64a.exe
    Details|contains: \WINDOWS\system32\Drivers\PROCEXP152.SYS
  condition: selection and not filter
falsepositives:
  - Other legimate tools using this service names and drivers. Note - clever attackers may easily bypass this detection by just renaming the services. Therefore just Medium-level and don't rely on it.
level: medium
license: DRL-1.1
related:
  - id: f2485272-a156-4773-82d7-1d178bc4905b
    type: derived