DSHIELD

Hunt Hypothesis

This detection identifies potential malicious activity by leveraging the DSHIELD YARA signature to flag known threat indicators within Azure Sentinel workloads. Proactively hunting for this behavior allows the SOC team to validate low-severity signals against current infrastructure, ensuring early identification of emerging threats before they escalate into significant incidents.

YARA Rule

rule DSHIELD: Packer PEiD
{
      meta:
		author="malware-lu"
strings:
		$a0 = { 06 E8 [2] 5E 83 EE ?? 16 17 9C 58 B9 [2] 25 [2] 2E }

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 DSHIELD detection rule in a legitimate enterprise environment, along with targeted filtering strategies:

• Scenario: Automated Endpoint Protection Scans by Defender for Endpoint

  • Context: Microsoft Defender for Endpoint (MDE) or CrowdStrike Falcon agents perform routine real-time scanning and scheduled deep scans of the file system. The YARA rule may detect the scanning engine’s own process (MsMpEng.exe or csfalcon.sys) as a potential threat when it accesses protected directories or modifies quarantine logs, triggering DSHIELD alerts due to signature overlap.
  • Filter/Exclusion: Create an exclusion based on the Process Name and Parent Process. Exclude any event where the process name matches known EDR executables (e.g., MsMpEng.exe, csfalcon.sys) when the parent process is the same EDR service or a system scheduler (svchost.exe with specific service ID).

• Scenario: Scheduled Software Deployment via SCCM/Intune

  • Context: During business hours, System Center Configuration Manager (SCCM) or Microsoft Intune pushes application updates and patches. The deployment agent (ccmexec.exe) often extracts installation packages to temporary directories, which may contain files matching the DSHIELD YARA signatures intended for malicious binaries, causing false triggers during mass rollout windows.
  • Filter/Exclusion: Implement a Time-Based Exclusion combined with Process Path. Exclude alerts generated by ccmexec.exe or intunagent.exe running from the standard deployment paths (e.g., C:\Windows\CCM\ or C:\Program Files\Microsoft Intune Management Extension) between 09:00 and 17:00 local time.

• Scenario: Legacy Backup Operations by Veeam or Commvault