Sigma rule: Potential Privilege Escalation Using Symlink Between Osk and Cmd

Rule

Title

Potential Privilege Escalation Using Symlink Between Osk and Cmd

Status

test

Level

high

Author

frack113

Date

2022-12-11

Modified

2022-12-20

File

rules/windows/process_creation/proc_creation_win_cmd_mklink_osk_cmd.yml

Commit

ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects the creation of a symbolic link between "cmd.exe" and the accessibility on-screen keyboard binary (osk.exe) using "mklink". This technique provides an elevated command prompt to the user from the login screen without the need to log in.

Log source

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_*

False positives (as the rule lists them)

• Unknown

Tags

• attack.privilege-escalation
• attack.persistence
• attack.t1546.008

MITRE ATT&CK ids this rule names

• T1546.008

References

• https://github.com/redcanaryco/atomic-red-team/blob/5c1e6f1b4fafd01c8d1ece85f510160fc1275fbf/atomics/T1546.008/T1546.008.md
• https://ss64.com/nt/mklink.html

Read on 2026-11-03T00:58:21.399Z under licence sigma-drl-1.1@d5f4c36a from https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules/windows/process_creation/proc_creation_win_cmd_mklink_osk_cmd.yml