bambam001bedrock

Hunt Hypothesis

This detection identifies potential low-severity file artifacts matching the specific “bambam001bedrock” signature, which may indicate early-stage reconnaissance or benign activity that requires contextual validation. Proactive hunting for this pattern in Azure Sentinel is essential to distinguish between false positives and subtle adversary footprints before they escalate into more significant threats within the environment.

YARA Rule

rule bambam001bedrock
{
      meta:
		author="malware-lu"
strings:
		$a0 = { 6A 14 E8 9A 05 00 00 8B D8 53 68 [4] E8 6C FD FF FF B9 05 00 00 00 8B F3 BF [4] 53 F3 A5 E8 8D 05 00 00 8B 3D [4] A1 [4] 66 8B 15 [4] B9 [4] 2B CF 89 45 E8 89 0D [4] 66 89 55 EC 8B 41 3C 33 D2 03 C1 83 C4 10 66 8B 48 06 66 8B 50 14 81 E1 FF FF 00 00 8D 5C 02 18 8D 41 FF 85 C0 }

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 bambam001bedrock detection rule, including targeted filters and exclusions:

• Scenario: Scheduled Antivirus Definition Updates

  • Context: The enterprise uses Microsoft Defender for Endpoint or Symantec Endpoint Protection, which performs daily definition updates via a scheduled task. These updates often involve the extraction of large compressed archives containing new signature databases, triggering file creation and memory scanning patterns that mimic the rule’s logic.
  • Filter/Exclusion: Add an exclusion for the specific process path C:\Program Files\Microsoft Defender\MpCmdRun.exe (or equivalent for Symantec) when running under the “System” user account during business hours (09:00–17:00). Alternatively, exclude file paths containing \Windows\Temp\AntivirusUpdate\.

• Scenario: Automated Backup and Archiving Jobs

  • Context: The organization utilizes Veeam Backup & Replication or Commvault to run nightly incremental backups. These tools create temporary staging files and compress data blocks in the background, which can generate high-frequency file I/O and memory allocation patterns that resemble the behavioral indicators of the bambam001bedrock rule.
  • Filter/Exclusion: Create a whitelist for processes named VeeamTransportService.exe or CommServeBackupAgent.exe. Filter out alerts where the parent process is identified as the backup service and the file extension is .vbk, .v2i, or .bck.

• Scenario: Enterprise Software Deployment via SCCM/Intune

  • Context: IT administrators use Microsoft Endpoint Configuration Manager (SCCM) or Microsoft Intune to push application updates (e.g., Office 365 ProPlus, Adobe Acrobat DC) to