AnskyaNTPackerGeneratorAnskya

Hunt Hypothesis

This detection identifies the presence of the Anskya NTPacker Generator tool, which adversaries often utilize to construct custom network traffic packers for obfuscating command-and-control communications or data exfiltration activities. Proactively hunting for this artifact in Azure Sentinel is essential because its deployment may signal early-stage reconnaissance or a sophisticated evasion strategy that could bypass standard signature-based defenses if not explicitly monitored.

YARA Rule

rule AnskyaNTPackerGeneratorAnskya
{
      meta:
		author="malware-lu"
strings:
		$a0 = { 55 8B EC 83 C4 F0 53 B8 88 1D 00 10 E8 C7 FA FF FF 6A 0A 68 20 1E 00 10 A1 14 31 00 10 50 E8 71 FB FF FF 8B D8 85 DB 74 2F 53 A1 14 31 00 10 50 E8 97 FB FF FF 85 C0 74 1F 53 A1 14 31 00 10 50 E8 5F FB FF FF 85 C0 74 0F 50 E8 5D FB FF FF 85 C0 74 05 E8 70 FC FF FF 5B E8 F2 F6 FF FF 00 00 48 45 41 52 54 }

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 3-5 specific false positive scenarios for the AnskyaNTPackerGeneratorAnskya detection rule, including suggested filters and exclusions:

• Scenario: Automated Patch Deployment via SCCM/Intune

  • Context: Enterprise endpoints running Microsoft Endpoint Configuration Manager (SCCM) or Intune often utilize third-party packaging tools to wrap standard installers. When the deployment agent executes a script to generate an NTP-compatible package for a new security update, it may invoke the AnskyaNTPackerGenerator utility in memory, triggering the YARA rule.
  • Suggested Filter/Exclusion: Create an exclusion based on the parent process name and user context. Exclude alerts where the parent process is ccmexec.exe (SCCM) or Microsoft.IntuneManagementAgent.exe running under a system account (NT AUTHORITY\SYSTEM) or a dedicated deployment service account.
  • Filter Logic: (Process.Name == "AnskyaNTPackerGenerator*" AND Parent.ProcessName IN ("ccmexec.exe", "Microsoft.IntuneManagementAgent.exe") AND User.Context == "System/Service")

• Scenario: Scheduled Backup and Archiving Jobs

  • Context: Legacy file archiving solutions or custom backup scripts often run nightly to compress and package logs. If the organization uses a script that invokes AnskyaNTPackerGenerator as part of a PowerShell scheduled task (Task Scheduler) to bundle network traffic logs for compliance, this legitimate activity will match the YARA signature.
  • Suggested Filter/Exclusion: Exclude alerts originating from specific Scheduled Task IDs or file paths known to host backup agents. Focus on excluding processes running in the C:\Program Files\BackupAgent directory during off-hours (e.g., 02:00–04:00).