Toward a general defense against kernel queue hooking attacks

Abstract

Kernel queue hooking (KQH) attacks achieve stealthy malicious function execution by embedding malicious hooks in dynamic kernel schedulable queues (K-Queues). Because they keep kernel code and persistent hooks intact, they can evade detection of state-of-the-art kernel integrity monitors. Moreover, they have been used by advanced malware such as the Rustock spam bot to achieve malicious goals. In this paper, we present a systematic defense against such novel attacks. We propose the Precise Lookahead Checking of function Pointers approach that checks the legitimacy of pending K-Queue callback requests by proactively checking function pointers that may be invoked by the callback function. To facilitate the derivation of specifications for any K-Queue, we build a unified static analysis framework and a toolset that can derive from kernel source code properties of legitimate K-Queue requests and turn them into source code for the runtime checker. We implement proof-of-concept runtime checkers for four K-Queues in Linux and perform a comprehensive experimental evaluation of these checkers, which shows that our defense is effective against KQH attacks.