yodasProtectorV1032AshkbizDanehkar

Hunt Hypothesis

This rule targets the execution of the Yodas Protector, a lightweight process hollowing and injection tool often used by adversaries to hide malicious code within legitimate processes. Proactively hunting for this indicator in Azure Sentinel allows the SOC to identify early-stage post-exploitation activity that may evade traditional signature-based detections.

YARA Rule

rule yodasProtectorV1032AshkbizDanehkar
{
      meta:
		author="malware-lu"
strings:
		$a0 = { E8 03 00 00 00 EB 01 ?? BB 55 00 00 00 E8 03 00 00 00 EB 01 ?? E8 8F 00 00 00 E8 03 00 00 00 EB 01 ?? E8 82 00 00 00 E8 03 00 00 00 EB 01 ?? E8 B8 00 00 00 E8 03 00 00 00 EB 01 ?? E8 AB 00 00 00 E8 03 00 00 00 EB 01 ?? 83 FB 55 E8 03 00 00 00 EB 01 ?? 75 2E E8 03 00 00 00 EB 01 ?? C3 60 E8 00 00 00 00 5D 81 ED 94 73 42 00 8B D5 81 C2 E3 73 42 00 52 E8 01 00 00 00 C3 C3 E8 03 00 00 00 EB 01 ?? E8 0E 00 00 00 E8 D1 FF FF FF C3 E8 03 00 00 00 EB 01 ?? 33 C0 64 FF 30 64 89 20 CC C3 E8 03 00 00 00 EB 01 ?? 33 C0 64 FF 30 64 89 20 4B CC C3 E8 03 00 00 00 EB 01 ?? 33 DB B9 BF A4 42 00 81 E9 8E 74 42 00 8B D5 81 C2 8E 74 42 00 8D 3A 8B F7 33 C0 E8 03 00 00 00 EB 01 ?? E8 17 00 00 00 90 90 90 E9 63 29 00 00 33 C0 64 FF 30 64 89 20 43 CC C3 }

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 Application Deployment: The rule likely targets specific byte patterns or string signatures associated with the “Yodas Protector” packer, which is sometimes used in older or niche .NET applications to reduce size or obfuscate code. This can trigger on legitimate business applications (e.g., internal inventory management tools) that were packed years ago and have not been recompiled.
  • Filter/Exclusion: Exclude files located in specific application directories (e.g., C:\Program Files\InternalTools\) or allowlist specific executable names (e.g., InventoryManager.exe) if the application version is known to use this packer.
• Third-Party Installer or Updater: Many third-party software installers (e.g., Adobe Creative Cloud, Java JRE, or specific vendor-specific updaters) use custom packers or obfuscation techniques that may coincidentally match the YARA signature. This often occurs during scheduled automated patching cycles.
  • Filter/Exclusion: Exclude processes running from standard installer directories (e.g., C:\Windows\Installer\, C:\ProgramData\Package Cache\) or allowlist specific parent processes known to launch installers (e.g., msiexec.exe, setup.exe from known vendor paths).
• Development Environment Artifacts: In development environments, developers may use specific build tools, obfuscators, or test harnesses that incorporate the “Yodas Protector” library or similar packing algorithms for testing purposes. This can trigger on temporary build outputs or test executables in developer workstations.
  • Filter/Exclusion: Exclude files in common development directories (e.g., C:\Users\<user>\source\repos\, C:\dev\builds\) or allowlist processes spawned by IDEs or build tools (e.g., dotnet.exe, `msbuild.exe