Kernel-mode code signing is the Windows requirement that a driver be digitally signed before it can load into the kernel. The signature lets Windows verify the driver’s publisher and helps block unknown or tampered code from running at ring 0, where it can control files, memory, processes, and security settings.
This matters because kernel access is powerful: a signed driver can still be dangerous if its design is too broad, if it has a vulnerable interface, or if attackers can abuse a legitimate driver for defense evasion. In real attacks, criminals often use trusted or stolen-signed drivers to load malicious kernel code, disable security tools, or manipulate protected system state. Defenders rely on code signing, Secure Boot, driver blocklists, and monitoring of driver loads, but signature status alone is not proof of safety.