nPackV112002006BetaNEOxuinC

Hunt Hypothesis

This detection identifies the presence of a specific YARA-matched artifact (nPackV112002006BetaNEOxuinC) that may indicate an early-stage adversary activity or a known benign process requiring verification within the Azure Sentinel environment. Proactive hunting for this signature is essential to distinguish between legitimate baseline behavior and potential low-severity indicators of compromise, ensuring that subtle threats are not overlooked before they escalate into critical incidents.

YARA Rule

rule nPackV112002006BetaNEOxuinC
{
      meta:
		author="malware-lu"
strings:
		$a0 = { 83 3D 40 [3] 00 75 05 E9 01 00 00 00 C3 E8 41 00 00 00 B8 80 [3] 2B 05 08 [3] A3 3C [3] E8 5E 00 00 00 E8 EC 01 00 00 E8 F8 06 00 00 E8 03 06 00 00 A1 3C [3] C7 05 40 [3] 01 00 00 00 01 05 00 [3] FF 35 00 [3] C3 C3 }

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 4 specific false positive scenarios for the detection rule nPackV112002006BetaNEOxuinC, including context and recommended filters:

• Scenario: Automated Endpoint Protection Scans by CrowdStrike Falcon

  • Context: The YARA signature nPackV112002006BetaNEOxuinC matches the behavior of the CrowdStrike Falcon sensor during its scheduled hourly “On-Demand Scan” or real-time file indexing. When the sensor scans a large directory containing nested archives, it generates temporary unpacking processes that mimic the signature’s heuristic for unknown executable extraction.
  • Suggested Filter: Exclude alerts where the parent process is FalconSensor.exe (CrowdStrike) and the execution path resides within the standard installation directory (C:\Program Files\CrowdStrike\). Additionally, filter out events occurring during the defined maintenance window (e.g., 02:00–04:00 local time).

• Scenario: Microsoft System Center Configuration Manager (SCCM) Application Deployment

  • Context: During a scheduled software deployment job for “Office 365 ProPlus,” SCCM utilizes the ccmsetup.exe installer to unpack and stage application packages. The rule triggers because the staging process extracts .msi or .cab files containing embedded scripts that match the NeoXuinC pattern, specifically when deploying updates to a high-volume user group.
  • Suggested Filter: Create an exclusion for processes spawned by ccmsetup.exe where the command line contains arguments related to “AppDeployment” or specific Application IDs (e.g., --appID=Office365). Limit this to the SCCM site server IP range and the known distribution point subnets.

• Scenario: Backup Agent Activity (Veeam Backup & Replication