Windows Privilege Escalation via mklink Symlink Between cmd.exe and osk.exe

Alerts on mklink creating a symlink between osk.exe and cmd.exe, enabling potential login-screen privilege escalation.

FreeReviewedSigma · High · v2

Product: windows
Category: process_creation
Author: frack113 (SigmaHQ), DRL 1.1
Published: 2022-12-11
Updated: 2026-07-31

ATT&CK techniques

Persistence → Priv Esc

Recon
Resource Dev
Initial Access
Execution
Persistence
- T1546.008Accessibility Features
Priv Esc
- T1546.008Accessibility Features
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule flags process creation where a symbolic link is created using mklink involving osk.exe and cmd.exe, with cmd.exe targeted by filename and command-line arguments. This behavior can enable execution of an elevated command prompt from the login screen without requiring a user login. The detection relies on Windows process creation telemetry capturing the executing image (cmd.exe) and the full command line containing mklink, osk.exe, and cmd.exe.

Reporting behind it

Related detections9 linkedT1546.008 — drag to rearrange

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Malicious Stickey Key Called CMD via Command Execution - Hash Detection (via process_creation)

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Malicious Accessibility Feature Backdoor via Image File Execution Options Debugger (via registry_set)

Malicious Stickey Key Called CMD via Command Execution (via process_creation)

Malicious Sticky Key Sethc Command for Replacement by CMD (via process_creation)

Malicious Stickey Key IFEO - Reg via Command (via process_creation)

Malicious Accessibility Feature Debugger Hijack via IFEO (via registry_set)

Windows Process Creation: Suspicious secedit.exe Security Policy Export or Configuration

Windows Privilege Escalation via mklink Symlink Between cmd.exe and osk.exe

Pivot detection · T1546.008 · 9 related

Changelog

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-mklink-symlink-from-osk-exe-to-cmd-exe-for-login-screen-privilege-escala-e9b61244

title: Windows Privilege Escalation via mklink Symlink Between cmd.exe and osk.exe
id: d64f1887-82cb-4c0d-b5cb-9da5ee1ba485
status: test
description: This rule flags process creation where a symbolic link is created using mklink involving osk.exe and cmd.exe, with cmd.exe targeted by filename and command-line arguments. This behavior can enable execution of an elevated command prompt from the login screen without requiring a user login. The detection relies on Windows process creation telemetry capturing the executing image (cmd.exe) and the full command line containing mklink, osk.exe, and cmd.exe.
references:
  - https://github.com/redcanaryco/atomic-red-team/blob/5c1e6f1b4fafd01c8d1ece85f510160fc1275fbf/atomics/T1546.008/T1546.008.md
  - https://ss64.com/nt/mklink.html
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/process_creation/proc_creation_win_cmd_mklink_osk_cmd.yml
author: frack113, Huntrule Team
date: 2022-12-11
modified: 2022-12-20
tags:
  - attack.privilege-escalation
  - attack.persistence
  - attack.t1546.008
logsource:
  product: windows
  category: process_creation
detection:
  selection_img:
    - Image|endswith: \cmd.exe
    - OriginalFileName: Cmd.Exe
  selection_cli:
    CommandLine|contains|all:
      - mklink
      - \osk.exe
      - \cmd.exe
  condition: all of selection_*
falsepositives:
  - Unknown
level: high
regression_tests_path: regression_data/rules/windows/process_creation/proc_creation_win_cmd_mklink_osk_cmd/info.yml
license: DRL-1.1
related:
  - id: e9b61244-893f-427c-b287-3e708f321c6b
    type: derived

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