Hackers are using open source software that’s popular with video game cheaters to allow their Windows-based malware to bypass restrictions Microsoft put in place to prevent such infections from occurring.

The software comes in the form of two software tools that are available on GitHub. Cheaters use them to digitally sign malicious system drivers so they can modify video games in ways that give the player an unfair advantage. The drivers clear the considerable hurdle required for the cheat code to run inside the Windows kernel, the fortified layer of the operating system reserved for the most critical and sensitive functions.

Researchers from Cisco’s Talos security team said Tuesday that multiple Chinese-speaking threat groups have repurposed the tools—one called HookSignTool and the other FuckCertVerifyTimeValidity. Instead of using the kernel access for cheating, the threat actors use it to give their malware capabilities it wouldn’t otherwise have.

The technique Talos has discovered represents a new way to bypass Windows driver restrictions. It exploits a loophole that has existed since the start of the policy that grandfathers in older drivers even when they haven’t been reviewed for safety by Microsoft. The exception, designed to ensure older software was still able to run on Windows systems, is triggered when a driver is signed by a Windows-trusted certificate authority prior to July 29, 2015.