Android Platform Modeling and Android App Verification in the ACL2 Theorem Prover

We present our work in using the ACL2 theorem prover to formally model the Android platform and to formally verify Android apps. Our approach allows the verification of the full functional correctness of apps as well as security properties. It also lets us detect or prove the absence of “functional malware”, malicious app functionality that is triggered by complex conditions on state and that causes the app to calculate the wrong results or otherwise behave incorrectly. Our formal Android model is an executable simulator of a growing subset of the Android platform, and app proofs are done by automated symbolic execution of the app’s event handlers using the formal model. By induction, we prove that an app satisfies an invariant, including the correctness properties of interest, for all possible sequences of events.