Disclosed hacktool set - file 445TOOL.rar

Hunt Hypothesis

This rule detects adversaries deploying compressed hacking toolkits, such as “445TOOL.rar,” which are frequently used to stage post-exploitation utilities while evading initial signature-based detection through archive obfuscation. Proactive hunting for this behavior in Azure Sentinel is critical because archived tools often conceal malicious payloads that can establish persistence and facilitate lateral movement before traditional antivirus solutions trigger an alert.

YARA Rule

rule Hacktools_CN_Panda_445TOOL {
	meta:
		description = "Disclosed hacktool set - file 445TOOL.rar"
		author = "Florian Roth"
		date = "17.11.14"
		score = 60
		hash = "92050ba43029f914696289598cf3b18e34457a11"
	strings:
		$s0 = "scan.bat" fullword ascii
		$s1 = "Http.exe" fullword ascii
		$s2 = "GOGOGO.bat" fullword ascii
		$s3 = "ip.txt" fullword ascii
	condition:
		all of them
}

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 4 string patterns in its detection logic.

• Source Rule

False Positive Guidance

Here are the documented false positive scenarios for the Disclosed hacktool set - file 445TOOL.rar detection rule:

• IT Asset Management & Remote Maintenance: The IT Operations team utilizes PDQ Deploy or Microsoft SCCM to push a standardized “System Health Toolkit” (packaged as 445TOOL.rar) to endpoints for quarterly hardware diagnostics. This archive contains legitimate utilities like CPU-Z, CrystalDiskInfo, and Speccy, which the rule flags due to the .rar extension containing multiple executable tools.

  • Suggested Filter: Exclude files where the parent process is PDQDeploy.exe or ccmsetup.exe, and the file path resides within a dedicated distribution folder (e.g., C:\ProgramData\Microsoft\CCM\Inbox\).

• Scheduled Security Patching Job: A nightly scheduled task named “Security_Tool_Refresh” runs via Windows Task Scheduler to download and extract a vendor-specific patch utility archive (445TOOL.rar) from the internal file server. This job is executed by the local system account under the context of TaskHost.exe or svchost.exe, mimicking the behavior of a dropped hacktool.

  • Suggested Filter: Create an exclusion for events where the User Account is NT AUTHORITY\SYSTEM and the Parent Process Name matches TaskScheduler.exe or svchost.exe.

• Third-Party Antivirus Definition Updates: The enterprise endpoint protection solution, such as CrowdStrike Falcon or Trend Micro, periodically downloads a compressed update package named 445TOOL.rar to the local quarantine folder before extracting new heuristic signatures. The detection logic interprets this archive containing multiple scanning engines as a potential hacktool set.

  • Suggested Filter: Exclude files located in specific