Armadillov430v440SiliconRealmsToolworks

Hunt Hypothesis

This rule identifies the presence of specific malware strains associated with the Armadillo, v430, v440, Silicon Realms, and Toolworks families, which are often used for initial access or lateral movement. Proactively hunting for these signatures allows the SOC to detect low-severity threats that may be evading standard behavioral detections and establish a foothold within the Azure environment.

YARA Rule

rule Armadillov430v440SiliconRealmsToolworks
{
      meta:
		author="malware-lu"
strings:
		$a0 = { 55 8B EC 6A FF 68 40 [2] 00 68 80 [2] 00 64 A1 00 00 00 00 50 64 89 25 00 00 00 00 83 EC 58 53 56 57 89 65 E8 FF 15 88 [2] 00 33 D2 8A D4 89 15 30 [2] 00 8B C8 81 E1 FF 00 00 00 89 0D 2C [2] 00 C1 E1 08 03 CA 89 0D 28 [2] 00 C1 E8 10 A3 24 }
	$a1 = { 60 E8 00 00 00 00 5D 50 51 0F CA F7 D2 9C F7 D2 0F CA EB 0F B9 EB 0F B8 EB 07 B9 EB 0F 90 EB 08 FD EB 0B F2 EB F5 EB F6 F2 EB 08 FD EB E9 F3 EB E4 FC E9 9D 0F C9 8B CA F7 D1 59 58 50 51 0F CA F7 D2 9C F7 D2 0F CA EB 0F B9 EB 0F B8 EB 07 B9 EB 0F 90 EB 08 }

condition:
		$a0 at pe.entry_point or $a1 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 2 string patterns in its detection logic.

• Source Rule

False Positive Guidance

• Scenario: A DevOps engineer runs the armadillo CLI tool (version 4.30 or 4.40) during a scheduled CI/CD pipeline job to validate silicon realm configurations for new microservice deployments. The tool’s binary or script matches the YARA signature due to its specific version string and structural markers.

  • Filter/Exclusion: Exclude processes where the parent process is powershell.exe or bash.exe initiated by a known CI/CD agent (e.g., jenkins.exe, gitlab-runner, azure-pipelines-agent) and the working directory is under the standard build artifact path (e.g., C:\builds\ or /home/ci/builds/).

• Scenario: An IT administrator performs a manual audit of legacy application binaries in the SiliconRealms vendor-specific directory (e.g., C:\Program Files\SiliconRealms\Toolworks\) using a file integrity monitoring (FIM) agent that scans for known tool signatures. The YARA rule matches the static binary of the Toolworks utility, which is a legitimate vendor-provided diagnostic tool.

  • Filter/Exclusion: Exclude files whose full path contains SiliconRealms\Toolworks and whose SHA256 hash matches the known good baseline hash for the Toolworks utility (e.g., abc123...). Alternatively, exclude if the file owner is SYSTEM or a dedicated service account like svc-siliconrealms.

• Scenario: A security team runs a YARA scan across the endpoint using a tool like yara64 or ClamAV to verify detection coverage. The scan process itself loads the Armadillov430v440SiliconRealmsToolworks rule file into memory, and if the