PeX099bartCrackPl

Hunt Hypothesis

This detection identifies potential password cracking or brute-force attacks by analyzing process execution patterns associated with the BartCrack utility via a specialized YARA signature. Proactively hunting for this behavior in Azure Sentinel allows the SOC team to uncover stealthy credential compromise attempts that may evade standard alerting thresholds, ensuring early intervention before adversaries gain persistent access.

YARA Rule

rule PeX099bartCrackPl
{
      meta:
		author="malware-lu"
strings:
		$a0 = { E9 F5 [3] 0D 0A C4 C4 C4 C4 C4 C4 C4 C4 C4 C4 C4 C4 C4 C4 C4 C4 C4 C4 C4 C4 C4 }

condition:
		$a0 at pe.entry_point
}

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 1 string patterns in its detection logic.

• Source Rule

False Positive Guidance

Here are 4 specific false positive scenarios for the PeX099bartCrackPl detection rule, including suggested filters and exclusions:

• Scenario: Legitimate Software Deployment via SCCM/Intune

  • Context: System Center Configuration Manager (SCCM) or Microsoft Intune agents often execute installation packages containing cracked executables or repackaged installers that match the signature of known cracking tools. These deployments usually run under the ccmexec.exe or msiexec.exe process tree during maintenance windows.
  • Suggested Filter: Exclude processes where the parent executable is ccmexec.exe, Microsoft.Windows.Update.Agent.exe, or msiexec.exe. Additionally, filter out events occurring on known deployment servers (e.g., HostID containing “SCCM-01”) during standard maintenance hours (02:00–06:00).

• Scenario: Automated Patch Management with Repackaged Installers

  • Context: Third-party patch management tools like Ivanti or ManageEngine often utilize repackaged installers that include embedded cracking logic to bypass license checks during the installation phase. This triggers the rule when the tool extracts and executes these components in the C:\ProgramData\Ivanti directory.
  • Suggested Filter: Create a path-based exclusion for directories commonly used by patch management tools, such as C:\Program Files\Ivanti\LANDESK Agent, C:\ProgramData\ManageEngine, and C:\Windows\CCM. Exclude events where the file hash matches known good baseline hashes of these specific vendor installers.

• Scenario: Scheduled Backup and Imaging Jobs

  • Context: Enterprise backup solutions like Veeam or Acronis often utilize “crack” utilities within their imaging engines to handle license verification for large-scale