yPv10bbyAshkbizDanehkar

Hunt Hypothesis

This hypothesis detects potential low-severity file-based threats identified by the specific YARA signature “yPv10bbyAshkbizDanehkar,” which may indicate early-stage malware or benign artifacts requiring contextual analysis. The SOC team should proactively hunt for this signal in Azure Sentinel to validate false positives and uncover subtle adversary behaviors that might be overlooked by standard high-severity alerts, ensuring comprehensive coverage of the attack surface.

YARA Rule

rule yPv10bbyAshkbizDanehkar
{
      meta:
		author="malware-lu"
strings:
		$a0 = { 55 8B EC 53 56 57 60 E8 00 00 00 00 5D 81 ED 4C 32 40 00 E8 03 00 00 00 EB 01 ?? B9 EA 47 40 00 81 E9 E9 32 40 00 8B D5 81 C2 E9 32 40 00 8D 3A 8B F7 33 C0 E8 04 00 00 00 90 EB 01 C2 E8 03 00 00 00 EB 01 ?? AC [7] EB 01 E8 }

condition:
		$a0
}

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 4 specific false positive scenarios for the detection rule yPv10bbyAshkbizDanehkar, tailored to a legitimate enterprise environment:

• Endpoint Protection Scans by CrowdStrike Falcon

  • Scenario: The CrowdStrike Falcon sensor performs scheduled real-time and on-demand scans of the C:\ProgramData directory. During these scans, the YARA signature matches the Falcon scanner’s own executable or its temporary quarantine files, triggering a false alert as if a new threat was detected within that specific path.
  • Suggested Filter: Exclude processes where process_name equals csfalcon.exe (CrowdStrike) and the file extension is .exe located in the C:\ProgramData\CrowdStrike\ directory.

• Microsoft Defender for Endpoint Antivirus Updates

  • Scenario: The Microsoft Defender service (MsMpEng.exe) automatically downloads and installs definition updates via Windows Update. The YARA rule detects the unpacking of the update package (.cab or .msi files) in the C:\Program Files\Windows Defender\ folder, mistaking the legitimate update extraction for a suspicious file execution pattern.
  • Suggested Filter: Create an exclusion for parent process MsMpEng.exe when the target file path contains \Windows Defender\ and the event type is “File Creation” or “Process Start”.

• System Center Configuration Manager (SCCM) Deployment Jobs

  • Scenario: A nightly scheduled job via SCCM deploys a new application package to workstations. The deployment agent (ccmsetup.exe) extracts installation files into the C:\Windows\CCMCache directory. The YARA rule triggers on these extracted temporary files which match the signature of known benign enterprise software patterns.
  • Suggested Filter: Exclude alerts where the