Windows Process Creation: Suspicious Command-Line Path Traversal Evasion Strings

Flags Windows command-line strings that look like “..\” path traversal evasion attempts, excluding known Google Drive and Citrix launcher patterns.

FreeUnreviewedSigmamediumv1

windows-process-creation-suspicious-command-line-path-traversal-evasion-strings-1327381e

title: "Windows Process Creation: Suspicious Command-Line Path Traversal Evasion Strings"
id: 219760a2-f3ee-4667-aa18-67d2a453ec3e
status: test
description: This rule identifies Windows process creation events where the command line contains suspicious traversal or obfuscation patterns resembling bogus “..\” sequences that reference Windows or System32 paths. Attackers may use these strings to evade naive path checks or influence how applications resolve file locations. It relies on process creation telemetry with both the process image path and the full command-line text.
references:
  - https://twitter.com/hexacorn/status/1448037865435320323
  - https://twitter.com/Gal_B1t/status/1062971006078345217
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/process_creation/proc_creation_win_susp_commandline_path_traversal_evasion.yml
author: Christian Burkard (Nextron Systems), Huntrule Team
date: 2021-10-26
modified: 2023-03-29
tags:
  - attack.stealth
  - attack.t1036
logsource:
  category: process_creation
  product: windows
detection:
  selection_1:
    Image|contains: \Windows\
    CommandLine|contains:
      - \..\Windows\
      - \..\System32\
      - \..\..\
  selection_2:
    CommandLine|contains: .exe\..\
  filter_optional_google_drive:
    CommandLine|contains: \Google\Drive\googledrivesync.exe\..\
  filter_optional_citrix:
    CommandLine|contains: \Citrix\Virtual Smart Card\Citrix.Authentication.VirtualSmartcard.Launcher.exe\..\
  condition: 1 of selection_* and not 1 of filter_optional_*
falsepositives:
  - Google Drive
  - Citrix
level: medium
license: DRL-1.1
related:
  - id: 1327381e-6ab0-4f38-b583-4c1b8346a56b
    type: derived

What it detects

This rule identifies Windows process creation events where the command line contains suspicious traversal or obfuscation patterns resembling bogus “..\” sequences that reference Windows or System32 paths. Attackers may use these strings to evade naive path checks or influence how applications resolve file locations. It relies on process creation telemetry with both the process image path and the full command-line text.

Known false positives

Google Drive
Citrix

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