This detection identifies the presence of scan.exe, a known component of the Chinese Hacktool malware suite, which adversaries often deploy to establish persistence and conduct initial reconnaissance within Azure environments. Proactively hunting for this artifact is critical because its low severity classification may cause it to be overlooked during routine monitoring, allowing attackers to maintain a stealthy foothold before escalating their activities.
rule Tools_scan {
meta:
description = "Chinese Hacktool Set - file scan.exe"
author = "Florian Roth"
reference = "http://tools.zjqhr.com/"
date = "2015-06-13"
hash = "c580a0cc41997e840d2c0f83962e7f8b636a5a13"
strings:
$s2 = "Shanlu Studio" fullword wide
$s3 = "_AutoAttackMain" fullword ascii
$s4 = "_frmIpToAddr" fullword ascii
condition:
uint16(0) == 0x5a4d and filesize < 3000KB and all of them
}
This YARA rule can be deployed in the following contexts:
This rule contains 3 string patterns in its detection logic.
Here are 5 specific false positive scenarios for the Chinese Hacktool Set - file scan.exe detection rule in an enterprise environment, along with suggested filters or exclusions:
Scenario: Enterprise Antivirus On-Demand Scans
scan.exe to perform scheduled on-demand deep scans of user directories and system drives.TencentPCMgr.exe, 360tray.exe) or restrict the alert to only trigger if scan.exe is located outside standard installation paths like C:\Program Files\Tencent\....Scenario: Software Deployment and Patching Agents
scan.exe to inventory existing files before installing patches, particularly when managing legacy Chinese-language applications.svc-deploy, admin-patching) or filter by Command Line Arguments containing specific deployment flags (e.g., /inventory, -mode=pre-check).Scenario: Scheduled Disk Cleanup and Maintenance Jobs
scan.exe as its scanning engine) might execute to analyze temporary files