Windows process access indicating potential shellcode injection to lsass.exe

Alerts on high-privilege process access from wmiprvse.exe to lsass.exe consistent with potential shellcode injection behavior.

FreeReviewedSigma · Medium · v5
Product
windows
Category
process_access
Author
Bhabesh Raj (SigmaHQ), DRL 1.1
Published
2022-03-11
Updated
2026-07-31
title: Windows process access indicating potential shellcode injection to lsass.exe
id: f07d0001-9fd8-410d-9419-a5f0b9788428
status: test
description: This rule flags Windows process access events with specific GrantedAccess values and an associated call trace containing the string "UNKNOWN". The match is constrained to suspicious source/target process pairs involving Wmiprvse.exe accessing lsass.exe, while excluding several known benign Dell and Visual Studio program-to-program patterns. It matters because abnormal access to sensitive processes like lsass.exe can be used to support covert code execution, and the detection relies on process access telemetry that records GrantedAccess, SourceImage, TargetImage, and call trace context.
references:
  - https://github.com/EmpireProject/PSInject
  - https://github.com/SigmaHQ/sigma/blob/master/rules-threat-hunting/windows/process_access/proc_access_win_susp_potential_shellcode_injection.yml
author: Bhabesh Raj, Huntrule Team
date: 2022-03-11
modified: 2024-07-02
tags:
  - attack.privilege-escalation
  - attack.stealth
  - attack.t1055
  - detection.threat-hunting
logsource:
  category: process_access
  product: windows
detection:
  selection:
    GrantedAccess:
      - "0x147a"
      - "0x1f3fff"
    CallTrace|contains: UNKNOWN
  filter_main_wmiprvse:
    SourceImage: C:\Windows\System32\Wbem\Wmiprvse.exe
    TargetImage: C:\Windows\system32\lsass.exe
  filter_optional_dell_folders:
    SourceImage|startswith:
      - C:\Program Files\Dell\
      - C:\Program Files (x86)\Dell\
    TargetImage|startswith:
      - C:\Program Files\Dell\
      - C:\Program Files (x86)\Dell\
  filter_optional_dell_specifc:
    SourceImage: C:\Program Files (x86)\Dell\UpdateService\ServiceShell.exe
    TargetImage: C:\Windows\Explorer.EXE
  filter_optional_visual_studio:
    SourceImage|startswith: C:\Program Files\Microsoft Visual Studio\
    TargetImage|startswith: C:\Program Files\Microsoft Visual Studio\
  condition: selection and not 1 of filter_main_* and not 1 of filter_optional_*
falsepositives:
  - Unknown
level: medium
license: DRL-1.1
related:
  - id: 250ae82f-736e-4844-a68b-0b5e8cc887da
    type: derived