Minke101byCodius

Hunt Hypothesis

This YARA rule targets the Minke101byCodius artifact, which likely indicates the presence of a specific malware strain or tooling used for initial access or execution. Proactively hunting for this signature in Azure Sentinel allows the SOC to identify compromised endpoints or suspicious file drops before the adversary can establish persistence or escalate privileges.

YARA Rule

rule Minke101byCodius
{
      meta:
		author="malware-lu"
strings:
		$a0 = { 55 8B EC 83 C4 F0 53 [5] 10 E8 7A F6 FF FF BE 68 66 00 10 33 C0 55 68 DB 40 00 10 64 FF 30 64 89 20 E8 FA F8 FF FF BA EC 40 00 10 8B C6 E8 F2 FA FF FF 8B D8 B8 6C 66 00 10 8B 16 E8 88 F2 FF FF B8 6C 66 00 10 E8 76 F2 FF FF 8B D0 8B C3 8B 0E E8 E3 E4 FF FF E8 2A F9 FF FF E8 C1 F8 FF FF B8 6C 66 00 10 8B 16 E8 6D FA FF FF E8 14 F9 FF FF E8 AB F8 FF FF 8B 06 E8 B8 E3 FF FF 8B D8 B8 6C 66 00 10 E8 38 F2 FF FF 8B D3 8B 0E E8 A7 E4 FF [4] C4 FB FF FF E8 E7 F8 FF FF 8B C3 E8 B0 E3 FF FF E8 DB F8 FF FF 33 C0 5A 59 59 64 89 10 68 E2 40 00 10 C3 E9 50 EB FF FF EB F8 5E 5B E8 BB EF FF FF 00 00 00 43 41 31 38 }

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

• Scenario: A developer or DevOps engineer is compiling a custom C/C++ utility or a small internal microservice using gcc or clang on a build server or developer workstation. The resulting binary contains specific string literals or structural patterns that match the heuristic or signature defined in the Minke101byCodius YARA rule.

  • Filter/Exclusion: Exclude files located in standard build directories (e.g., C:\Projects\*\build\, C:\src\*\dist\) or exclude executables with extensions like .exe or .bin if the rule is primarily targeting script interpreters or specific library formats. Alternatively, whitelist known compiler output paths.

• Scenario: An administrator is running a legitimate, signed third-party utility (such as a vendor-provided diagnostic tool, a backup agent, or a log rotation script) that was recently updated or deployed via a software distribution system (e.g., SCCM, Ansible, or Chef). The binary may contain embedded strings or code patterns that inadvertently trigger the YARA signature.

  • Filter/Exclusion: Exclude files with valid digital signatures from known trusted vendors (e.g., Microsoft, Veeam, Commvault) or exclude paths under standard application install directories (e.g., C:\Program Files\VendorName\).

• Scenario: A scheduled task or service is executing a PowerShell script or a Python script that has been compiled into a standalone executable using tools like PyInstaller or Nuitka for deployment convenience. The packaging process can introduce structural artifacts or string patterns that match the YARA rule.

  • Filter/Exclusion: Exclude executables located in temporary directories used for script compilation (e.g., C:\Temp\, C:\Users\*\AppData\Local\Temp\) or exclude files with names matching common packaging outputs