WASP: Stack protection for WebAssembly

WebAssembly is a binary executable format designed as a compilation target enabling high-level language code to be run natively in web browsers, JavaScript runtimes, and standalone interpreters. Previous work has highlighted WebAssembly’s vulnerability to traditional memory exploits, such as stack smashing (stack-based buffer overflows), when compiled from memory-unsafe languages. Such vulnerabilities are used as a component in impactful end-to-end exploits, hence the design and implementation in WebAssembly of mitigations against memory exploits, such as stack canaries, is needed. We present WASP, an implementation of stack-based buffer overflow protection using stack canaries within Emscripten, the leading C and C ++ to WebAssembly compiler. Further, we provide an extension to the standard stack smashing protection design, offering extra security against canary leak attacks by randomizing the canary on a per-function call basis. We verify WASP’s effectiveness against proof-of-concept exploits. Evaluation results show that the overheads brought by WASP on execution time, executable binary size, and compilation workflow are negligible to low in all platforms considered: the Chromium web browser, the Node.js JavaScript runtime, as well as the standalone WebAssembly runtimes Wasmer and WAVM.