Result: Exploiting Mixed Binaries

Unsafe programming systems are still very popular, despite the shortcomings due to several published memory-corruption vulnerabilities. Toward defending memory corruption, compilers have started to employ advanced software hardening such as Control-flow Integrity (CFI) and SafeStack. However, there is a broad interest for realizing compilers that impose memory safety with no heavy runtime support (e.g., garbage collection). Representative examples of this category are Rust and Go, which enforce memory safety primarily statically at compile time. Software hardening and Rust/Go are promising directions for defending memory corruption, albeit combining the two is questionable. In this article, we consider hardened mixed binaries, i.e., machine code that has been produced from different compilers and, in particular, from hardened C/C++ and Rust/Go (e.g., Mozilla Firefox, Dropbox, npm, and Docker). Our analysis is focused on Mozilla Firefox, which outsources significant code to Rust and is open source with known public vulnerabilities (with assigned CVE). Furthermore, we extend our analysis in mixed binaries that leverage Go, and we derive similar results. The attacks explored in this article do not exploit Rust or Go binaries that depend on some legacy (vulnerable) C/C++ code. In contrast, we explore how Rust/Go compiled code can stand as a vehicle for bypassing hardening in C/C++ code. In particular, we discuss CFI and SafeStack, which are available in the latest Clang. Our assessment concludes that CFI can be completely nullified through Rust or Go code by constructing much simpler attacks than state-of-the-art CFI bypasses.