Escargot01finalMeat

Hunt Hypothesis

This detection identifies the presence of the Escargot malware’s final meat payload within Azure Sentinel, signaling a potential post-exploitation activity where adversaries establish persistence or prepare for data exfiltration. Proactively hunting for this signature is essential to uncover stealthy infections that may have bypassed initial perimeter defenses and are now operating silently within the internal network environment.

YARA Rule

rule Escargot01finalMeat
{
      meta:
		author="malware-lu"
strings:
		$a0 = { EB 04 40 30 2E 31 60 68 61 [3] 64 FF 35 00 00 00 00 64 89 25 00 00 00 00 B8 92 [3] 8B 00 FF D0 50 B8 CD [3] 81 38 DE C0 37 13 75 2D 68 C9 [3] 6A 40 68 00 ?? 00 00 68 00 00 [2] B8 96 [3] 8B 00 FF D0 8B 44 24 F0 8B 4C 24 F4 EB 05 49 C6 04 01 40 0B C9 75 F7 BE 00 10 [2] B9 00 [2] 00 EB 05 49 80 34 31 40 0B C9 75 F7 58 0B C0 74 08 33 C0 C7 00 DE C0 AD 0B BE [4] E9 AC 00 00 00 8B 46 0C BB 00 00 [2] 03 C3 50 50 }

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 Escargot01finalMeat detection rule, including suggested filters and exclusions:

• Scenario: Scheduled Antivirus Definition Updates

  • Context: The YARA rule may flag the large binary updates downloaded by enterprise antivirus suites (e.g., Microsoft Defender, CrowdStrike Falcon) as suspicious due to their size or embedded scripts. This often occurs during nightly maintenance windows when MsMpSvc or FalconService processes update packages.
  • Filter/Exclusion: Create a process-based exclusion for the specific service executables (e.g., C:\Program Files\Microsoft Defender\MsMpEng.exe) and restrict detection to business hours only, excluding the 02:00–04:00 maintenance window.

• Scenario: Software Deployment via SCCM/Intune

  • Context: During mass software deployments using Microsoft Endpoint Configuration Manager (SCCM) or Intune, deployment agents (ccmsetup.exe or intunagent.exe) extract and execute temporary installation packages that match the rule’s signature patterns. This is common when rolling out new versions of Office 365 or Adobe Creative Cloud.
  • Filter/Exclusion: Exclude alerts where the parent process is identified as a known deployment agent (e.g., ccmexec.exe, intunagent.exe) and the file path contains standard deployment directories like \Windows\CCMCache or \ProgramData\Microsoft\IntuneManagementExtension.

• Scenario: Backup Agent Data Processing

  • Context: Enterprise backup solutions (e.g., Veeam, Rubrik, Commvault) frequently process large data blocks and generate temporary manifests that trigger the rule. The YARA signature might interpret the high I/O activity and specific header structures of these backup agents as anomalous behavior typical of