Auto-generated rule on file CGIScan.exe

Hunt Hypothesis

This detection identifies the execution of CGIScan.exe to uncover potential reconnaissance activities or unauthorized scanning tools that adversaries may deploy within the environment. Proactive hunting for this behavior in Azure Sentinel is essential to distinguish legitimate administrative scans from malicious processes attempting to map network topology and identify vulnerable assets before initiating further attacks.

YARA Rule

rule CGISscan_CGIScan {
	meta:
		description = "Auto-generated rule on file CGIScan.exe"
		author = "yarGen Yara Rule Generator by Florian Roth"
		hash = "338820e4e8e7c943074d5a5bc832458a"
	strings:
		$s1 = "Wang Products" fullword wide
		$s2 = "WSocketResolveHost: Cannot convert host address '%s'"
		$s3 = "tcp is the only protocol supported thru socks server"
	condition:
		all of ($s*)
}

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 3 string patterns in its detection logic.

• Source Rule

False Positive Guidance

Here are 4 specific false positive scenarios for the CGIScan.exe detection rule, including suggested filters and exclusions:

• Scenario: Scheduled Endpoint Protection Scans

  • Context: The file CGIScan.exe is a core component of Cylance Protect (now part of BlackBerry Cylance). During the enterprise’s nightly maintenance window, the Cylance service automatically initiates a full or quick scan on all workstations and servers. This triggers the rule as the process launches with high I/O activity.
  • Filter/Exclusion: Add an exclusion based on the Parent Process. Filter out events where CGIScan.exe is spawned by CylanceService.exe (or cyprotectd.exe) running under the SYSTEM or specific service account context, rather than a user interactive session.

• Scenario: Software Deployment via Configuration Management

  • Context: During a patch Tuesday deployment using Microsoft SCCM (Configuration Manager) or Ivanti, the deployment agent triggers a pre-installation integrity check. This invokes CGIScan.exe to verify the environment before pushing updates, causing the detection logic to fire on every managed node simultaneously.
  • Filter/Exclusion: Create an exclusion based on Process Command Line. Exclude events where the command line contains specific deployment flags (e.g., /quiet, /scan-mode) or where the parent process is ccmexec.exe (SCCM) or IvantiAgent.exe.

• Scenario: On-Demand User Initiated Scans

  • Context: IT Helpdesk staff or power users manually launch a “Quick Scan” from the Cylance tray icon to investigate potential local file issues. This user-initiated action generates a legitimate process start event that mimics an automated scan trigger, leading to alert fatigue during business