Upackv036alphaDwing

Hunt Hypothesis

This detection identifies potential malicious activity involving the unpacking of specific alpha-stage Dwing artifacts, which often serve as indicators for early-stage fileless or obfuscated threats. Proactively hunting for this behavior in Azure Sentinel allows the SOC team to uncover stealthy adversary movements that may evade standard signature-based defenses before they escalate into critical incidents.

YARA Rule

rule Upackv036alphaDwing
{
      meta:
		author="malware-lu"
strings:
		$a0 = { AB E2 E5 5D 59 8B 76 68 51 59 46 AD 85 C0 }

condition:
		$a0
}

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 Upackv036alphaDwing detection rule, including suggested filters and exclusions:

• Scenario: Automated Software Deployment via SCCM/Intune

  • Context: System Center Configuration Manager (SCCM) or Microsoft Intune agents frequently unpack compressed installer packages (.zip, .7z) containing nested archives during scheduled maintenance windows. The YARA rule may flag the extraction process of these legitimate deployment payloads as suspicious “unpacking” behavior associated with the Dwing malware family.
  • Filter/Exclusion: Add an exclusion for processes running under the CCMExec.exe (SCCM) or Microsoft.IntuneManagementAgent service accounts. Specifically, exclude file paths containing \Windows\CCM\ or \Program Files\Microsoft Intune Agent\.

• Scenario: Enterprise Antivirus Real-Time Scanning

  • Context: Endpoint Detection and Response (EDR) solutions like CrowdStrike Falcon or SentinelOne often perform real-time heuristic scanning on compressed files. When a user downloads a large archive, the EDR engine may spawn a child process to unpack and scan it in memory, triggering the Upackv036alphaDwing signature due to the specific byte patterns of the extraction routine.
  • Filter/Exclusion: Create a rule exception for processes where the parent process is the primary antivirus service (e.g., csfalcon.exe, SentinelOneAgent.exe). Filter out alerts where the file extension being processed is .zip or .cab and the user context is a standard domain user rather than an interactive admin session.

• Scenario: Scheduled Backup and Archiving Jobs

  • Context: Enterprise backup tools such as Veeam Agent for Windows or Acronis Cyber Protect run scheduled jobs that extract temporary archives to verify integrity before