muckisprotectorImucki

Hunt Hypothesis

This YARA rule targets the “muckisprotectorImucki” signature, likely indicating the presence of a specific malware strain or crypter that adversaries may deploy to establish persistence or execute payloads. Proactively hunting for this indicator allows the SOC to identify low-severity infections early, preventing potential lateral movement or privilege escalation within the Azure Sentinel environment.

YARA Rule

rule muckisprotectorImucki
{
      meta:
		author="malware-lu"
strings:
		$a0 = { BE [4] B9 [4] 8A 06 F6 D0 88 06 46 E2 F7 E9 }

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 legacy Java-based application server (e.g., Tomcat or JBoss) running a custom in-house “Mucki” business logic module that uses the imucki library for internal data protection. The YARA rule matches the specific byte sequence of the muckisprotector class loader within the JVM heap or native library.
  • Filter/Exclusion: Exclude processes where the parent process is java.exe or jvm.dll and the command line contains -Dmucki.protector=true or references the specific JAR file muckisprotector-1.2.jar.
• Scenario: An IT admin manually deploys a new version of the “Mucki Security Agent” via a PowerShell script during a patch Tuesday maintenance window. The agent binary (muckisprotector.exe) is copied to C:\Program Files\Mucki\ and executed to register itself with the service control manager.
  • Filter/Exclusion: Exclude events where the process path is C:\Program Files\Mucki\muckisprotector.exe and the parent process is powershell.exe or cmd.exe with a command line containing New-Service or sc create.
• Scenario: A scheduled task named “Mucki Daily Integrity Check” runs every night at 02:00 AM. This task executes muckisprotector.exe --verify to scan for tampering in protected application directories. The YARA rule triggers on the execution of the verification binary.
  • Filter/Exclusion: Exclude events where the process name is muckisprotector.exe and the command line contains --verify or --check, and the parent process is svchost.exe (specifically the Task Scheduler service) or Task Scheduler process.