Chinese Hacktool Set - file hscan.exe

Hunt Hypothesis

This hypothesis posits that adversaries are deploying the hscan.exe utility from a known Chinese hacktool set to perform initial reconnaissance and system enumeration within Azure environments. The SOC team should proactively hunt for this artifact because its presence often signals early-stage lateral movement or data staging activities by state-sponsored actors targeting intellectual property, even when individual events trigger only low-severity alerts.

YARA Rule

rule CN_Tools_hscan {
	meta:
		description = "Chinese Hacktool Set - file hscan.exe"
		author = "Florian Roth"
		reference = "http://tools.zjqhr.com/"
		date = "2015-06-13"
		hash = "17a743e40790985ececf5c66eaad2a1f8c4cffe8"
	strings:
		$s1 = "%s -f hosts.txt -port -ipc -pop -max 300,20 -time 10000" fullword ascii
		$s2 = "%s -h 192.168.0.1 192.168.0.254 -port -ftp -max 200,20" fullword ascii
		$s3 = "%s -h www.target.com -all" fullword ascii
		$s4 = ".\\report\\%s-%s.html" fullword ascii
		$s5 = ".\\log\\Hscan.log" fullword ascii
		$s6 = "[%s]: Found cisco Enable password: %s !!!" fullword ascii
		$s7 = "%s@ftpscan#FTP Account:  %s/[null]" fullword ascii
		$s8 = ".\\conf\\mysql_pass.dic" fullword ascii
	condition:
		uint16(0) == 0x5a4d and filesize < 300KB and 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 8 string patterns in its detection logic.

References

False Positive Guidance

Here are 5 specific false positive scenarios for the Chinese Hacktool Set - hscan.exe detection rule, tailored for an enterprise environment:

Antivirus Endpoint Scans via Third-Party Solutions
- Scenario: Enterprise deployments of Chinese-origin security suites (e.g., Trend Micro Deep Security, Kingsoft Office Security, or Huawei CloudEngine) often utilize hscan.exe as their primary real-time scanning engine. This file is frequently triggered during routine full-system scans initiated by the central management console, particularly when scanning large data repositories on file servers.
- Filter/Exclusion: Create an exclusion for processes named hscan.exe that are spawned directly by known parent security services (e.g., tmagent.exe, ksafe.exe) and restrict the rule to only alert if the process originates from a non-standard user context or lacks a valid digital signature from the vendor’s certificate authority.
Scheduled Patch Management and Integrity Checks
- Scenario: IT Operations teams often schedule nightly maintenance jobs using tools like Microsoft SCCM (ConfigMgr) or Ansible to deploy updates for Chinese software stacks. These jobs may invoke hscan.exe as a pre-deployment integrity checker to verify the hash of application binaries before installation, triggering the detection during the 02:00–04:00 UTC maintenance window.
- Filter/Exclusion: Implement a time-based filter that suppresses alerts for hscan.exe activity occurring between 01:00 and 05:00 local time on weekdays, or exclude the specific file path associated with the patch management agent’s working directory (e.g., C:\Program Files\SCCM\Updates\).
Software Asset Inventory Scanning
- Scenario: Automated asset discovery tools such as **SolarW