Potentially Suspicious NTFS Symlink Behavior Change (via process_creation)

title: Potentially Suspicious NTFS Symlink Behavior Change (via process_creation)
id: a8ae4444-614e-5a53-8100-3b74a458fd0c
status: stable
description: This rule detects the modification of NTFS symbolic link behavior using fsutil, which could be used to enable remote to local or remote to remote symlinks for potential attacks.
references:
    - https://attack.mitre.org/techniques/T1222/001/
    - https://attack.mitre.org/techniques/T1059/
    - https://www.cybereason.com/blog/cybereason-vs.-blackcat-ransomware
    - https://learn.microsoft.com/fr-fr/windows-server/administration/windows-commands/fsutil-behavior
    - https://thedfirreport.com/2025/06/30/hide-your-rdp-password-spray-leads-to-ransomhub-deployment/
author: Huntrule Team
date: 2026-05-20
tags:
    - attack.execution
    - attack.defense-impairment
    - attack.t1059
    - attack.t1222.001
logsource:
    category: process_creation
    product: windows
detection:
    selection_img_proxy:
        - Image|endswith:
              - '\cmd.exe'
              - '\powershell.exe'
              - '\pwsh.exe'
        - OriginalFileName:
              - 'Cmd.Exe'
              - 'PowerShell.EXE'
              - 'pwsh.dll'
    selection_fsutil_cli:
        CommandLine|contains|all:
            - 'fsutil'
            - 'behavior'
            - 'set'
            - 'SymlinkEvaluation'
    selection_symlink_params:
        CommandLine|contains:
            - 'R2L:1'
            - 'R2R:1'
            - 'L2L:1'
    condition: all of selection_*
falsepositives:
    - Unknown
level: medium