Secure Dynamic Code Generation Against Spraying

DCG (Dynamic Code Generation) technologies have found widely applications in the Web 2.0 era, Dion Blazakis recently presented a Flash JIT-Spraying attack against Adobe Flash Player that easily circumvented DEP and ASLR protection mechanisms built in modern operating systems. We have generalized and extended JIT Spraying into DCG Spraying. Based our analyses on this abstract model of DCG Spraying, we have found that all mainstream DCG implementations (Java / JavaScript / Flash /.Net/ SilverLight) are vulnerable against DCG Spraying attack, and none of the existing ad hoc defenses such as compilation optimization, random NOP padding and constant splitting provides effective protection. Furthermore, we propose a new protection method, INSeRT, which combines randomization of intrinsic elements of machine instructions and randomly planted special trapping snippets. INSeRT practically renders the "sprayed code " ineffective, while alerts the host program of ongoing attacking attempts. We implemented a prototype of INSeRT on the V8 JavaScript engine, and the performance overhead is less than 5%, which should be acceptable in practical application