Detects exploit artifact for WT-2025-0050, authentication bypass through QCommand argument injection

Hunt Hypothesis

This hunt hypothesis targets adversaries attempting to bypass authentication controls by injecting malicious arguments into the QCommand process, a technique indicative of the WT-2025-0050 exploit. Proactively hunting for this artifact in Azure Sentinel is critical because successful exploitation allows attackers to gain unauthorized access without triggering standard login alerts, potentially leading to undetected lateral movement and data exfiltration.

YARA Rule

rule SUSP_EXPL_CommVault_CVE_2025_57791_Artifact_Aug25 {
   meta:
      description = "Detects exploit artifact for WT-2025-0050, authentication bypass through QCommand argument injection"
      reference = "https://labs.watchtowr.com/guess-who-would-be-stupid-enough-to-rob-the-same-vault-twice-pre-auth-rce-chains-in-commvault/"
      author = "X__Junior"
      date = "2025-08-21"
      score = 75
      id = "9ac37635-fd8b-5241-abc2-bf39bab5ccdf"
   strings:
      $sa1 = "_localadmin__"
      $sa2 = /-cs [a-zA-Z0-9-{}]{3,32} -cs /

      $sb2 = "-localadmin" base64
      $sb1 = "-localadmin"
   condition:
      filesize < 20MB and all of ($sa*) and 1 of ($sb*)
}

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 4 string patterns in its detection logic.

References

False Positive Guidance

Here are 4 specific false positive scenarios for the WT-2025-0050 detection rule, detailing legitimate enterprise activities that mimic authentication bypass via QCommand argument injection:

Scenario: Automated Patch Deployment via SCCM/Intune
- Context: System Center Configuration Manager (SCCM) or Microsoft Intune agents execute scheduled patching tasks using wusa.exe or custom PowerShell scripts. These tools often invoke the Windows Update Standalone Installer with a /quiet flag and inject specific command-line arguments via the QCommand parameter to suppress UI prompts during off-hours maintenance windows.
- Filter/Exclusion: Create an exclusion based on the process image path (e.g., C:\Program Files\Microsoft Configuration Manager\ccmexec.exe) and filter for user context “NT AUTHORITY\SYSTEM” or specific service accounts (e.g., DOMAIN\PatchSvc). Additionally, exclude events where the command line contains known benign flags like /quiet, /norestart, or /package.
Scenario: Endpoint DLP Policy Enforcement
- Context: Enterprise Data Loss Prevention (DLP) solutions such as Microsoft Purview Information Protection or Symantec DLP run background services that scan files and enforce policies. These agents frequently utilize the QCommand interface to trigger immediate classification scans or quarantine actions on specific file types without requiring user interaction, often passing complex JSON payloads in the argument string.
- Filter/Exclusion: Exclude processes matching known DLP agent binaries (e.g., C:\Program Files\Microsoft Purview\DlpAgent.exe). Implement a filter that allows events where the command line arguments contain specific keywords like “ScanPolicy”, “ClassifyFile”, or “QuarantineAction” and are initiated by the local system account.
Scenario: Legacy Reporting Tool Execution
- **Context