Donald Bren School of Information and Computer Sciences

Java Bytecode Verification was so far mostly approached from a correctness perspective. Security vulnerabilities have been found repeatedly and were corrected shortly thereafter. However, correctness is not the only potential point of failure in the verifier idea. In this paper we construct Java code, which is correct, but requires an excessive amount of time to prove safety. In contrast to previous flaws in the bytecode verifier, the enabling property for this exploit lies in the verification algorithm itself and not in the implementation and is thus not easily fixable. We explain how this architectural weakness could be exploited for denial-of-service attacks on JVM-based services and devices.