MSLRHV031emadicius

Hunt Hypothesis

This hunt hypothesis targets adversaries leveraging specific YARA signatures to identify known malware or suspicious executable behaviors that may evade standard detection thresholds. Proactively hunting for this indicator in Azure Sentinel allows the SOC team to uncover early-stage threats and validate their presence across endpoints before they escalate into more severe incidents.

YARA Rule

rule MSLRHV031emadicius
{
      meta:
		author="malware-lu"
strings:
		$a0 = { 60 D1 CB 0F CA C1 CA E0 D1 CA 0F C8 EB 01 F1 }

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

Here are 5 specific false positive scenarios for the MSLRHV031emadicius detection rule, tailored for a legitimate enterprise environment:

• Scenario: The Microsoft Defender Antivirus service (MsMpEng.exe) performs an on-demand or scheduled scan of the C:\Windows\System32 directory. During this process, the scanner extracts and analyzes embedded resources within system DLLs that match the Emadicius signature pattern (e.g., specific PE header structures or embedded certificates), triggering a hit even though no malicious activity is present.

  • Suggested Filter: Exclude processes where ImageName equals MsMpEng.exe AND CommandLine contains keywords like “Scan” or “Update”.

• Scenario: The System Center Configuration Manager (SCCM) client (ccmexec.exe) executes a software update deployment task. As part of the installation routine, it extracts temporary installer packages (.msi/.exe) into the %TEMP% folder which contain Emadicius-like code signatures used by legitimate third-party vendors (e.g., Adobe or Microsoft Office updates), causing the YARA rule to flag these temporary artifacts as suspicious.

  • Suggested Filter: Exclude events where ImageName equals ccmexec.exe AND FileName contains “Temp” or is located within the %TEMP% directory path.

• Scenario: An automated PowerShell scheduled job runs nightly to perform log rotation and database maintenance. The script invokes a custom utility that parses XML configuration files containing specific binary structures similar to Emadicius indicators, leading to a detection when the rule scans the memory or file system during this high-volume data processing window.

  • Suggested Filter: Exclude events where ImageName equals powershell.exe AND CommandLine contains “Task Scheduler” or specific job names (e.g., “Log