Upackv024v028AlphaDwing

Hunt Hypothesis

This detection identifies potential malicious activity involving the Alpha Dwing unpacking mechanism, which adversaries often utilize to obfuscate payloads and evade signature-based defenses. Proactively hunting for this behavior in Azure Sentinel is essential to uncover stealthy execution chains that may bypass standard alerts due to their low severity classification.

YARA Rule

rule Upackv024v028AlphaDwing
{
      meta:
		author="malware-lu"
strings:
		$a0 = { BE 88 01 40 00 AD [2] 95 AD 91 F3 A5 AD }

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 Upackv024v028AlphaDwing detection rule, including suggested filters and exclusions:

• Scenario: Enterprise Deployment of Microsoft Office Updates via SCCM

  • Context: System Center Configuration Manager (SCCM) or Intune pushes cumulative updates to the “Office Click-to-Run” service. The update installer often extracts compressed archives containing multiple DLLs and executable components, triggering the unpacking logic in the YARA rule.
  • Filter/Exclusion: Add an exclusion path for the Office installation directory (e.g., C:\Program Files\Microsoft Office* or C:\Program Files (x86)\Microsoft Office Root\Office16) and exclude processes named setup.exe, OfficeClickToRun.exe, or msiexec.exe when running under the context of the SCCM service account (NT SERVICE\CcmExec).

• Scenario: Scheduled Antivirus Definition Updates

  • Context: Endpoint protection suites like CrowdStrike Falcon, Microsoft Defender for Endpoint, or Symantec perform scheduled definition updates. These agents download compressed update packages (.cab or .zip) and unpack them into the local quarantine or definition folder before applying signatures, mimicking the behavior of a malicious archive extraction.
  • Filter/Exclusion: Create a whitelist for known antivirus processes such as CSFalconService.exe, MsMpEng.exe, or Symantec Endpoint Protection. Additionally, exclude file paths matching the vendor’s specific update directory (e.g., %ProgramData%\CrowdStrike\Logs or %LocalAppData%\Microsoft\Windows Defender).

• Scenario: Automated Backup and Archive Processing by Veeam

  • Context: The organization runs nightly Veeam Backup & Replication jobs that process large `.vbk