hyingsPEArmorV076hying

Hunt Hypothesis

This YARA rule targets specific PE file characteristics associated with the “hyingsPEArmorV076hying” signature, likely indicating the presence of a custom or obfuscated executable that may be used for initial access or payload delivery. Proactively hunting for this pattern in Azure Sentinel allows the SOC team to identify low-severity, potentially stealthy artifacts that standard behavioral detections might miss, ensuring early visibility into unusual binary structures within the environment.

YARA Rule

rule hyingsPEArmorV076hying
{
      meta:
		author="malware-lu"
strings:
		$a0 = { E9 00 00 00 00 60 E8 14 00 00 00 5D 81 ED 00 00 00 00 6A ?? E8 A3 00 00 00 }

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

• Legacy .NET Framework Applications: Older internal line-of-business applications (e.g., legacy inventory management tools or custom HR portals) compiled with older versions of the .NET Framework (pre-4.5) often exhibit specific PE header characteristics or obfuscation patterns that align with this YARA signature.
  • Filter/Exclusion: Exclude files located in C:\Program Files\ or C:\Program Files (x86)\ where the executable name matches known legacy application binaries (e.g., LegacyInventory.exe, HRPortalClient.exe) and the file size is within a specific historical range.
• Third-Party Anti-Virus/EDR Exclusions: Some commercial security agents (e.g., older builds of CrowdStrike Falcon, Carbon Black, or Symantec Endpoint Protection) may have their own internal service executables or driver loaders that trigger this rule due to their specific packing or header structure.
  • Filter/Exclusion: Exclude processes or files where the parent process is a known security agent service (e.g., FalconService.exe, cb.exe, ccSvcHst.exe) or where the file path contains \CrowdStrike\, \CarbonBlack\, or \Symantec\.
• Scheduled Backup Agents: Enterprise backup solutions like Veeam Backup & Replication or Commvault often use specialized agent executables on client machines that may be packed or have unique PE structures to ensure compatibility across different Windows versions.
  • Filter/Exclusion: Exclude files where the path contains \Veeam\ or \Commvault\ and the executable name matches known agent binaries (e.g., VeeamAgent.exe, cvp.exe).
• Java Runtime Environment (JRE) Native Libraries: Certain native helper libraries or launchers associated with the Java Runtime Environment (JRE) or JDK, particularly