Malware
Uroburos
aka Snake
Uroburos is a driver for Windows, including a bypass of PatchGuard.
Uroburos, also known as Snake, is a Windows malware family operated by Turla.
Background
Uroburos is a Windows driver that incorporates a PatchGuard bypass. In the words of Andrzej Dereszowski and Matthieu Kaczmarek, "the techniques used demonstrate [their] excellent knowledge of Windows kernel internals."
Source: Malpedia (Fraunhofer FKIE).