DBPEv210DingBoy

Hunt Hypothesis

This detection identifies the presence of the DingBoy malware variant within the environment by leveraging specific YARA signatures to capture its unique behavioral patterns. Proactive hunting for this threat in Azure Sentinel is essential to uncover early-stage infections that may evade standard signature-based defenses and prevent potential lateral movement before escalation.

YARA Rule

rule DBPEv210DingBoy
{
      meta:
		author="malware-lu"
strings:
		$a0 = { EB 20 [32] 9C 55 57 56 52 51 53 9C E8 [4] 5D 81 ED [4] EB 58 75 73 65 72 33 32 2E 64 6C 6C ?? 4D 65 73 73 61 67 65 42 6F 78 41 ?? 6B 65 72 6E 65 6C }

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 DBPEv210DingBoy detection rule, including targeted filters and exclusions:

• Scenario: Microsoft Defender Antivirus Real-Time Protection Scans

  • Context: The MsMpEng.exe process (Microsoft Defender) frequently scans database files in real-time. When scanning large .mdf or .ldf files on SQL Server instances, the YARA rule may match the signature of the antivirus engine’s internal DLLs as a potential “DingBoy” artifact due to overlapping memory patterns.
  • Filter/Exclusion: Add an exclusion for the process path C:\Program Files\Microsoft Defender Antivirus\msmpeng.exe and exclude file extensions .mdf, .ldf, and .bak from the rule’s scope when executed by this specific parent process.

• Scenario: Scheduled SQL Server Maintenance Plans (DBCC CHECKDB)

  • Context: Enterprise environments often run nightly maintenance jobs using sqlagent.exe or custom PowerShell scripts to execute DBCC CHECKDB. These operations involve heavy I/O and memory allocation that mimic the behavior of the detected anomaly, particularly when accessing system databases like master or model.
  • Filter/Exclusion: Create a time-based exclusion for the rule between 01:00 and 05:00 local time on weekdays. Alternatively, exclude any process tree where the parent is SQLServerAgent.exe (PID > 1000) running on known SQL Server hostnames ending in -DB-PROD.

• Scenario: Oracle Database Backup Jobs via RMAN

  • Context: In hybrid environments utilizing Oracle alongside SQL, the Recovery Manager (rman.exe) or oracle.exe processes perform incremental backups that involve complex file locking and memory mapping. The YARA signature