Development
Kernel hooks: how interception works
How drivers intercept kernel calls legitimately — for debugging, monitoring, and research.
8 min read
Why hook at all
Kernel-mode hooks redirect a function call to your code first. Driver developers use them to trace calls during debugging, vendors use them for telemetry and hotpatching, and researchers use them to observe system behavior. The same mechanism is also abused — which is why understanding it matters for defense too.
The common techniques
At a high level there are three places to intercept: the dispatch table (IRP handlers), exported function prologues (inline patches), and official callback interfaces like PsSetCreateProcessNotifyRoutine. The first two require careful synchronization and are flagged by PatchGuard on Windows; the third is the supported, stable route.
Stay on the supported path
Signed drivers, official callback APIs, and filter frameworks (minifilter, WFP) cover almost every legitimate need — and they survive OS updates. We build custom driver work this way for clients: interception you can sign, ship, and maintain.