VTint: Protecting Virtual Function Tables’ Integrity
Chao Zhang , Chengyu Song , Kevin Zhijie Chen , Zhaofeng Chen , Dawn Song .
In the recent past, a number of approaches have been proposed to protect certain types of control data in a program, such as return addresses saved on the stack, rendering most traditional control flow hijacking attacks ineffective. Attackers, however, can bypass these defenses by launching advanced attacks that corrupt other data, e.g., pointers indirectly used to access code. One of the most popular targets is virtual table pointers (vfptr), which point to virtual function tables (vtable) consisting of virtual function pointers. Attackers can exploit vulnerabilities, such as use-after-free and heap overflow, to overwrite the vtable or vfptr, causing further virtual function calls to be hijacked (vtable hijacking). In this paper we propose a lightweight defense solution VTint to protect binary executables against vtable hijacking attacks. It uses binary rewriting to instrument security checks before virtual function dispatches to validate vtables’ integrity. Experiments show that it only introduces a low performance overhead (less than 2%), and it can effectively protect real-world vtable hijacking attacks.