Windows Process Creation: cmd.exe Spawned from Edge Elevation Service (CVE-2021-41379)

Alerts when cmd.exe or PowerShell spawns under Edge elevation service with SYSTEM integrity, consistent with CVE-2021-41379 exploitation.

FreeReviewedSigma · Critical · v5

Product: windows
Category: process_creation
Author: Florian Roth (Nextron Systems) (SigmaHQ), DRL 1.1
Published: 2021-11-22
Updated: 2026-07-31

Analysis Detection

ATT&CK techniques

Priv Esc

Recon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
- T1068Exploitation for Privilege Escalation
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule flags Windows process creation where cmd.exe (or PowerShell/pwsh) is launched as a child of the Microsoft Edge elevation service (elevation_service.exe) running with SYSTEM integrity. Such behavior is consistent with local privilege escalation attempts targeting a specific Edge elevation mechanism. Telemetry required includes process creation events with parent image path, child image name/path, and integrity level indicators.

Reporting behind it

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Windows Process Creation: cmd.exe Spawned from Edge Elevation Service (CVE-2021-41379)

Pivot detection · T1068 · 9 related

Changelog

v5
Candidate ingested via manual entry.2026-07-31
v4
Candidate ingested via manual entry.2026-07-31
v3
Candidate ingested via manual entry.2026-07-31
v2
Candidate ingested via manual entry.2026-07-31
v1
No changelog recorded for this version.2026-07-30

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

windows-potential-cve-2021-41379-installerfiletakeover-privilege-escalation-atte-af8bbce4

title: "Windows Process Creation: cmd.exe Spawned from Edge Elevation Service (CVE-2021-41379)"
id: b0423090-e6f1-4045-94ac-764c619d82fd
status: test
description: This rule flags Windows process creation where cmd.exe (or PowerShell/pwsh) is launched as a child of the Microsoft Edge elevation service (elevation_service.exe) running with SYSTEM integrity. Such behavior is consistent with local privilege escalation attempts targeting a specific Edge elevation mechanism. Telemetry required includes process creation events with parent image path, child image name/path, and integrity level indicators.
references:
  - https://web.archive.org/web/20220421061949/https://github.com/klinix5/InstallerFileTakeOver
  - https://www.bleepingcomputer.com/news/microsoft/new-windows-zero-day-with-public-exploit-lets-you-become-an-admin/
  - https://www.zerodayinitiative.com/advisories/ZDI-21-1308/
  - https://www.logpoint.com/en/blog/detecting-privilege-escalation-zero-day-cve-2021-41379/
  - https://github.com/SigmaHQ/sigma/blob/master/rules-emerging-threats/2021/Exploits/CVE-2021-41379/proc_creation_win_exploit_cve_2021_41379.yml
author: Florian Roth (Nextron Systems), Huntrule Team
date: 2021-11-22
modified: 2024-12-01
tags:
  - attack.privilege-escalation
  - attack.t1068
  - cve.2021-41379
  - detection.emerging-threats
logsource:
  category: process_creation
  product: windows
detection:
  selection_img:
    - Image|endswith:
        - \cmd.exe
        - \powershell.exe
        - \pwsh.exe
    - OriginalFileName:
        - Cmd.Exe
        - PowerShell.EXE
        - pwsh.dll
  selection_parent:
    ParentImage|endswith: \elevation_service.exe
    IntegrityLevel:
      - System
      - S-1-16-16384
  condition: all of selection_*
falsepositives:
  - Unknown
level: critical
license: DRL-1.1
related:
  - id: af8bbce4-f751-46b4-8d91-82a33a736f61
    type: derived

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