Use Short Name Path in Image

Hunt Hypothesis

Detect use of the Windows 8.3 short name. Which could be used as a method to avoid Image detection

Detection Rule

Sigma (Original)

title: Use Short Name Path in Image
id: a96970af-f126-420d-90e1-d37bf25e50e1
related:
    - id: 349d891d-fef0-4fe4-bc53-eee623a15969
      type: similar
status: test
description: Detect use of the Windows 8.3 short name. Which could be used as a method to avoid Image detection
references:
    - https://www.acunetix.com/blog/articles/windows-short-8-3-filenames-web-security-problem/
    - https://learn.microsoft.com/en-us/previous-versions/windows/it-pro/windows-2000-server/cc959352(v=technet.10)
    - https://twitter.com/frack113/status/1555830623633375232
author: frack113, Nasreddine Bencherchali
date: 2022-08-07
modified: 2025-10-20
tags:
    - attack.stealth
    - attack.t1564.004
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        Image|contains:
            - '~1\'
            - '~2\'
    filter_main_system_process:
        ParentImage:
            - 'C:\Windows\System32\Dism.exe'
            - 'C:\Windows\System32\cleanmgr.exe'  # Spawns DismHost.exe with a shortened username (if too long)
    filter_main_installers:
        - Image|contains|all:
              - '\AppData\'
              - '\Temp\'
        - Image|endswith:
              - '~1\unzip.exe'
              - '~1\7zG.exe'
    filter_optional_webex:
        ParentImage|endswith: '\WebEx\WebexHost.exe' # Spawns a shortened version of the CLI and Image processes
    filter_optional_thor:
        ParentImage|endswith: '\thor\thor64.exe'
    filter_optional_installshield:
        - Product: 'InstallShield (R)'
        - Description: 'InstallShield (R) Setup Engine'
        - Company: 'InstallShield Software Corporation'
    condition: selection and not 1 of filter_main_* and not 1 of filter_optional_*
falsepositives:
    - Applications could use this notation occasionally which might generate some false positives. In that case Investigate the parent and child process.
level: medium

KQL (Azure Sentinel)

imProcessCreate
| where (TargetProcessName contains "~1\\" or TargetProcessName contains "~2\\") and (not((((ParentProcessName in~ ("C:\\Windows\\System32\\Dism.exe", "C:\\Windows\\System32\\cleanmgr.exe")) or (ActingProcessName in~ ("C:\\Windows\\System32\\Dism.exe", "C:\\Windows\\System32\\cleanmgr.exe"))) or ((TargetProcessName contains "\\AppData\\" and TargetProcessName contains "\\Temp\\") or (TargetProcessName endswith "~1\\unzip.exe" or TargetProcessName endswith "~1\\7zG.exe"))))) and (not(((ParentProcessName endswith "\\WebEx\\WebexHost.exe" or ActingProcessName endswith "\\WebEx\\WebexHost.exe") or (ParentProcessName endswith "\\thor\\thor64.exe" or ActingProcessName endswith "\\thor\\thor64.exe") or (TargetProcessFileProduct =~ "InstallShield (R)" or TargetProcessFileDescription =~ "InstallShield (R) Setup Engine" or TargetProcessFileCompany =~ "InstallShield Software Corporation"))))

Required Data Sources

False Positive Guidance

• Applications could use this notation occasionally which might generate some false positives. In that case Investigate the parent and child process.

MITRE ATT&CK Context

• Technique: T1564.004 — T1564.004

References

• https://www.acunetix.com/blog/articles/windows-short-8-3-filenames-web-security-problem/
• https://learn.microsoft.com/en-us/previous-versions/windows/it-pro/windows-2000-server/cc959352(v=technet.10)
• https://twitter.com/frack113/status/1555830623633375232
• SigmaHQ Rule