Detects a suspicious path traversal into a Windows folder

Hunt Hypothesis

This detection rule identifies adversaries attempting to exploit path traversal vulnerabilities by accessing unauthorized directories within Windows environments, which often precedes data exfiltration or privilege escalation attacks. Proactively hunting for these suspicious access patterns in Azure Sentinel is critical to intercept early-stage reconnaissance activities before attackers can leverage the vulnerability to compromise sensitive system files or execute malicious payloads.

YARA Rule

rule SUSP_Reversed_Hacktool_Author : FILE {
   meta:
      description = "Detects a suspicious path traversal into a Windows folder"
      author = "Florian Roth (Nextron Systems)"
      reference = "https://hackingiscool.pl/cmdhijack-command-argument-confusion-with-path-traversal-in-cmd-exe/"
      date = "2020-06-10"
      score = 65
      id = "33e20d75-af07-5df2-82c3-c48aec37a947"
   strings:
      $x1 = "iwiklitneg" fullword ascii wide
      $x2 = " eetbus@ " ascii wide
   condition:
      filesize < 4000KB and
      1 of them
}

Deployment Notes

This YARA rule can be deployed in the following contexts:

Microsoft Defender for Endpoint — Custom indicators / advanced hunting
Email Gateway — Attachment scanning
File Share Monitoring — Periodic scanning of shared drives
YARA CLI — Manual threat hunting on endpoints

This rule contains 2 string patterns in its detection logic.

References

False Positive Guidance

Here are 5 specific false positive scenarios for the “Detects a suspicious path traversal into a Windows folder” rule, including suggested filters and exclusions:

Antivirus Real-Time Scanning
- Scenario: Major endpoint protection suites (e.g., Microsoft Defender Antivirus, CrowdStrike Falcon) frequently traverse deep paths within C:\Windows to scan system files, registry hives, or update definition databases in real-time. This often generates high volumes of path traversal events that mimic attack patterns.
- Suggested Filter/Exclusion: Create an exclusion rule based on the Process Name (MsMpEng.exe, CrowdStrike.exe) and restrict the scope to the C:\Windows\System32 directory, as these tools rarely need to traverse outside standard system directories during routine scans.
Scheduled System Maintenance Tasks
- Scenario: Windows Task Scheduler runs automated maintenance jobs (e.g., “Defrag,” “System Health Analyzer,” or “Update Cleanup”) that iterate through the C:\Windows directory structure to optimize disk space and verify integrity. These tasks often use wildcards in their path arguments, triggering traversal alerts.
- Suggested Filter/Exclusion: Exclude events where the Process Name is svchost.exe or taskscheduler.exe AND the Command Line contains keywords like “maintenance,” “cleanup,” or specific Task IDs known to run during off-hours (e.g., 02:00–04:00).
Software Deployment and Patching Agents
- Scenario: Enterprise management tools such as Microsoft Endpoint Configuration Manager (SCCM), Ivanti, or PDQ Deploy actively traverse the C:\Windows folder to verify patch installation status, read system configuration files, or deploy new updates. This behavior is common during maintenance windows.
- **S