Alloyv1x2000

Hunt Hypothesis

This detection identifies potential malware or suspicious artifacts matching the specific Alloyv1x2000 signature within Azure Sentinel’s workload protection data. Proactively hunting for this behavior allows the SOC team to validate false positives and uncover early-stage threats that may evade standard high-severity alerts due to their low initial severity classification.

YARA Rule

rule Alloyv1x2000
{
      meta:
		author="malware-lu"
strings:
		$a0 = { 9C 60 E8 02 [3] 33 C0 8B C4 83 C0 04 93 8B E3 8B 5B FC 81 EB 07 20 40 ?? 87 DD 6A 04 68 ?? 10 [2] 68 ?? 02 [2] 6A ?? FF 95 46 23 40 ?? 0B }

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 Alloyv1x2000 detection rule, including targeted filters and exclusions:

• Scenario: Scheduled Antivirus Definition Updates

  • Context: The enterprise’s endpoint protection suite (e.g., CrowdStrike Falcon or Microsoft Defender) runs a nightly scheduled job to download and install new virus definition signatures. This process often involves the execution of a payload that matches the Alloyv1x2000 signature pattern due to shared code libraries in the update engine.
  • Filter/Exclusion: Create an exclusion based on the Process Name (falcon.sysmon.exe or MpCmdRun.exe) and restrict the rule trigger to business hours (e.g., 08:00–17:30) only, excluding the nightly maintenance window (22:00–04:00).

• Scenario: Deployment of Internal Patching Tool

  • Context: The IT Operations team utilizes a custom internal patching utility named “AlloyPatchManager” to push security updates across 5,000 workstations. This tool is compiled using the same framework that triggers the Alloyv1x2000 logic, causing alerts every time a patch is applied during the morning deployment cycle.
  • Filter/Exclusion: Add an exclusion for processes originating from the specific Installation Directory (C:\Program Files\InternalTools\AlloyPatchManager\) and filter by User Context, ensuring only alerts triggered by the SYSTEM or DOMAIN\Admins accounts are evaluated, while excluding standard user sessions.

• Scenario: Automated Backup Agent Execution

  • Context: The enterprise backup solution (e.g., Veeam or Acronis) runs a daily incremental backup job that invokes a helper utility