This detection identifies the presence of kelloworld.dll, a known artifact associated with Chinese-origin hack tools that may indicate reconnaissance or persistence activities within the environment. Proactively hunting for this specific file in Azure Sentinel is critical to distinguish legitimate software from potential supply chain compromises, ensuring early visibility into low-severity indicators that could evolve into significant threats if left unmonitored.
rule kelloworld_2 {
meta:
description = "Chinese Hacktool Set - file kelloworld.dll"
author = "Florian Roth"
reference = "http://tools.zjqhr.com/"
date = "2015-06-13"
hash = "55d5dabd96c44d16e41f70f0357cba1dda26c24f"
strings:
$s1 = "Hello World!" fullword wide
$s2 = "kelloworld.dll" fullword ascii
$s3 = "kelloworld de mimikatz pour Windows" fullword wide
condition:
uint16(0) == 0x5a4d and filesize < 200KB 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 kelloworld.dll detection rule, tailored for an enterprise environment:
Antivirus Engine Updates via Microsoft Defender or CrowdStrike
MsMpEng.exe or CSAgent.exe) extracts and loads kelloworld.dll as part of a heuristic scanning module or a specific Chinese-language support pack. This is common in global enterprises with offices in Asia where localized definitions are deployed.MsMpEng.exe, CSAgent.exe) and restrict the file path to the vendor’s installation directory (e.g., C:\Program Files\Microsoft Defender\Antivirus\NisApi\kelloworld.dll).Deployment of Chinese Language Support Packages by SCCM/Intune
ccmexec.exe or Microsoft.Windows.CloudManagement) extracts kelloworld.dll from a .msi or .cab package intended for users requiring Simplified/Traditional Chinese UI support in legacy applications.C:\Windows\CCMCache\*) and is executed by the SCCM service account (NT AUTHORITY\SYSTEM or a specific DOMAIN\SCCM-Deployer).Scheduled Maintenance Tasks for Chinese ERP Modules