MSLRHv032afakeSVKP111emadicius

Hunt Hypothesis

This detection identifies potential adversary activity involving the execution of suspicious binaries matching the specific YARA signature for fake SVK processes, which may indicate early-stage reconnaissance or fileless malware deployment. A proactive hunt is essential within Azure Sentinel to validate these low-severity alerts against known good baselines and prevent missed detections of stealthy threats that often evade standard rule-based monitoring.

YARA Rule

rule MSLRHv032afakeSVKP111emadicius
{
      meta:
		author="malware-lu"
strings:
		$a0 = { 60 E8 00 00 00 00 5D 81 ED 06 00 00 00 64 A0 23 00 00 00 83 C5 06 61 EB 05 E8 EB 04 40 00 EB FA E8 0A 00 00 00 E8 EB 0C 00 00 E8 F6 FF FF FF E8 F2 FF FF FF 83 C4 08 74 04 75 02 EB 02 EB 01 81 50 E8 02 00 00 00 29 5A 58 6B C0 03 E8 02 00 00 00 29 5A 83 C4 04 58 74 04 75 02 EB 02 EB 01 81 0F 31 50 0F 31 E8 0A 00 00 00 E8 EB 0C 00 00 E8 F6 FF FF FF E8 F2 FF FF FF 83 C4 08 2B 04 24 74 04 75 02 EB 02 EB 01 }

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 detection rule MSLRHv032afakeSVKP111emadicius, including suggested filters and exclusions:

• Scenario: Scheduled Antivirus Definition Updates

  • Context: Enterprise endpoints running Microsoft Defender for Endpoint or Symantec Endpoint Protection often trigger this rule during nightly definition updates. The YARA signature may match the specific hash pattern of the update service executable (MpCmdRun.exe or Smc.exe) when it spawns a temporary process to download and verify new virus signatures, mimicking the behavior of the targeted threat.
  • Filter/Exclusion: Exclude processes where the parent process is MsMpEng.exe (Microsoft Antimalware Service) or Smc.exe, specifically occurring between 02:00 and 04:00 UTC on weekdays.

• Scenario: Automated Patch Deployment via Configuration Management

  • Context: When SCCM (System Center Configuration Manager) or Ansible Tower pushes a cumulative update to the domain, the deployment agent (ccmsetup.exe or ansible-runner) executes a script that initializes a temporary verification service. This activity often matches the “fake SVK” signature logic within the rule due to similar registry key modifications and file creation patterns in the %TEMP% directory.
  • Filter/Exclusion: Create an exclusion for any process path containing \Microsoft SCCM\ or \Ansible\, provided the user context is SYSTEM or a dedicated service account (e.g., svc-patch-deploy).

• Scenario: Legacy Backup Agent Initialization

  • Context: Organizations utilizing Veeam Backup & Replication often run scheduled jobs that initialize a “fake” verification kernel before starting the actual backup stream. The Veeam transport service (`