Themida1201compressedOreansTechnologies

Hunt Hypothesis

This rule identifies the presence of Themida 12.01 compressed binaries, a common obfuscation technique used by adversaries to hide malicious payloads and evade static analysis. Proactively hunting for these artifacts in Azure Sentinel helps detect potentially compromised workloads or deployed tools that rely on commercial packers to obscure their true functionality.

YARA Rule

rule Themida1201compressedOreansTechnologies
{
      meta:
		author="malware-lu"
strings:
		$a0 = { B8 00 00 [2] 60 0B C0 74 58 E8 00 00 00 00 58 05 43 00 00 00 80 38 E9 75 03 61 EB 35 E8 00 00 00 00 58 25 00 F0 FF FF 33 FF 66 BB 19 5A 66 83 C3 34 66 39 18 75 12 0F B7 50 3C 03 D0 BB E9 44 00 00 83 C3 67 39 1A 74 07 2D 00 10 00 00 EB DA 8B F8 B8 }

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

• Legitimate Application Deployment (e.g., Adobe Creative Cloud, AutoCAD, or SolidWorks)

  • Scenario: IT administrators deploy commercial software packages that use Themida for code protection and compression to prevent reverse engineering. The YARA rule triggers on the executable files (e.g., acad.exe, photoshop.exe) during initial installation or patching.
  • Filter/Exclusion: Exclude known application directories such as C:\Program Files\Adobe\, C:\Program Files\Autodesk\, or C:\Program Files\SolidWorks Corp\. Alternatively, whitelist specific executable names known to use Themida (e.g., acad.exe, photoshop.exe, solidworks.exe).

• Legacy or Niche Business Software (e.g., SAP GUI, Oracle Client, or specialized ERP modules)

  • Scenario: Older or specialized enterprise applications often use Themida for obfuscation. Scheduled maintenance jobs or user logins trigger the execution of these binaries, causing the detection to fire repeatedly on servers or workstations.
  • Filter/Exclusion: Create a whitelist for specific legacy application paths (e.g., C:\Program Files\SAP\FrontEnd\, C:\Oracle\client\). If the software is critical, consider excluding the specific MD5/SHA256 hash of the binary if it remains consistent across versions.

• Development and Testing Environments (e.g., Visual Studio, JetBrains IDEs, or specific build tools)

  • Scenario: Developers may use third-party libraries or plugins that are protected by Themida. During build processes, unit tests, or local debugging sessions, these protected binaries are executed, triggering the rule on developer workstations or CI/CD agents.
  • Filter/Exclusion: Exclude paths associated with development environments such as `C:\Users<username>\App