Upackv037v038BetaStripbaserelocationtableOptionDwing

Hunt Hypothesis

This detection identifies potential obfuscation or packing anomalies in executable files where base relocation tables are stripped, a technique often employed by adversaries to evade static analysis and hide malicious payloads within legitimate processes. A SOC team should proactively hunt for this behavior in Azure Sentinel because such structural modifications can indicate early-stage evasion strategies used by advanced threats that might bypass standard signature-based defenses.

YARA Rule

rule Upackv037v038BetaStripbaserelocationtableOptionDwing
{
      meta:
		author="malware-lu"
strings:
		$a0 = { 53 18 33 C0 55 40 51 D3 E0 8B EA 91 FF 56 4C 33 }

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 Upackv037v038BetaStripbaserelocationtableOptionDwing detection rule, along with recommended filters and exclusions:

• Scenario: Microsoft Office Click-to-Run Self-Upgrades

  • Context: The OfficeClickToRun.exe process periodically extracts and unpacks update payloads (containing relocation tables) during scheduled maintenance windows. This activity often triggers the rule due to the beta stripping behavior of the updater’s internal DLLs.
  • Filter/Exclusion: Add a file path exclusion for C:\Program Files\Microsoft Office\root\Office16\ and process name exclusions for OfficeClickToRun.exe, OsfClientService.exe, and Setup.exe.

• Scenario: Antivirus Real-Time Scanning of Compressed Archives

  • Context: Endpoint Protection platforms like CrowdStrike Falcon, SentinelOne, or Microsoft Defender frequently unpack .zip or .cab files in a temporary directory to scan for embedded threats. The unpacking engine’s handling of relocation tables mimics the specific signature this rule detects.
  • Filter/Exclusion: Exclude processes belonging to major EDR vendors (e.g., C:\Program Files\CrowdStrike\csagent.exe, C:\Program Files\SentinelOne\SentinelOne\sentinel-service.exe) and exclude temporary directories such as %TEMP%\ or specific quarantine folders.

• Scenario: Scheduled PowerShell Deployment Scripts

  • Context: IT administrators often run scheduled PowerShell jobs (powershell.exe) that utilize the .NET Framework to deploy application updates via .msi or .cab packages. These scripts dynamically load assemblies with base relocation tables, triggering the detection logic during execution.
  • **Filter/