CrowdStrike’s Falcon software uses a special driver that allows it to run at a lower level than most apps so it can detect threats across a Windows system. Microsoft tried to restrict third parties from accessing the kernel in Windows Vista in 2006 but was met with pushback from cybersecurity vendors and EU regulators. However, Apple was able to lock down its macOS operating system in 2020 so that developers could no longer get access to the kernel.
Now, it looks like Microsoft wants to reopen the conversations around restricting kernel-level access inside Windows.
This is exactly how ebpf was implemented for the Linux kernel. You can build watchdog processes that can see what’s happening in the kernel and build kernel interrupts but it’s actually all executed in user space and not rewriting the kernel itself. Since it’s a proper api, it also means it’s incredibly hard to fundamentally break the system, unlike when you’re just blowing away kernel code with your own shit like all these security products do.