dUP2diablo2oo2

Hunt Hypothesis

This detection identifies potential file-based threats matching the “dUP2diablo2oo2” YARA signature, which may indicate early-stage malware or suspicious executable activity within the environment. Proactively hunting for this pattern in Azure Sentinel allows the SOC team to validate low-severity alerts before they escalate, ensuring rapid identification of novel or variant threats that might otherwise be overlooked by standard automated rules.

YARA Rule

rule dUP2diablo2oo2
{
      meta:
		author="malware-lu"
strings:
		$a0 = { E8 [4] E8 [4] 8B F0 6A 00 68 [4] 56 E8 [4] A2 [4] 6A 00 68 [4] 56 E8 [4] A2 [4] 6A 00 68 [4] 56 E8 [4] A2 [4] 68 [4] 68 [4] 56 E8 [4] 3C 01 75 19 BE [4] 68 00 02 00 00 56 68 }

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 3-5 specific false positive scenarios for the detection rule dUP2diablo2oo2, including suggested filters and exclusions tailored for an enterprise environment:

• Scenario: Scheduled Antivirus Definition Updates

  • Context: Enterprise endpoint protection suites (e.g., CrowdStrike Falcon, Microsoft Defender for Endpoint, or Symantec Endpoint Protection) frequently trigger this rule during their nightly scheduled definition update cycles. The YARA signature likely matches the specific hash or behavioral pattern of the updater service (C:\Program Files\...\UpdateService.exe) when it downloads and installs new signatures, mimicking the behavior of a potential threat deployment.
  • Suggested Filter/Exclusion: Create an exclusion based on the Process Name and File Path. Exclude any process matching *DefenderSvc.exe, *FalconSensor.exe, or *SymantecUpdate.exe located within their respective installation directories (e.g., C:\Program Files\Microsoft Defender\...).

• Scenario: Automated Software Deployment via Configuration Management

  • Context: During business hours, IT administrators utilize tools like Microsoft Endpoint Configuration Manager (MECM/SCCM) or Ansible Tower to push application patches and software installations. The deployment agent often executes scripts that unpack archives or modify system binaries in a way that triggers the dUP2diablo2oo2 logic, particularly when the rule detects specific file creation patterns associated with installer executables (e.g., msiexec.exe, wusa.exe).
  • Suggested Filter/Exclusion: Implement a filter based on the Parent Process and User Context. Exclude alerts where the parent process is ccmsetup.exe or Ansible-Runner.exe AND the user account belongs to the Domain Admins group or a specific service account (e.g.,