CVE-2019-7152 in Binaryen
Summary
by MITRE
A heap-based buffer over-read was discovered in wasm::WasmBinaryBuilder::processFunctions() in wasm/wasm-binary.cpp (when calling wasm::WasmBinaryBuilder::getFunctionIndexName) in Binaryen 1.38.22. A crafted input can cause segmentation faults, leading to denial-of-service, as demonstrated by wasm-opt.
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Analysis
by VulDB Data Team • 07/03/2023
The vulnerability identified as CVE-2019-7152 represents a critical heap-based buffer over-read flaw within the Binaryen compiler toolkit version 1.38.22. This issue specifically manifests in the wasm::WasmBinaryBuilder::processFunctions() method located in the wasm/wasm-binary.cpp file, where the function wasm::WasmBinaryBuilder::getFunctionIndexName is invoked. The flaw occurs when processing WebAssembly binary format inputs, making it particularly dangerous in environments where untrusted WebAssembly code is parsed or compiled. The vulnerability stems from insufficient bounds checking during the parsing of function index names within WebAssembly binary modules, creating a scenario where memory access exceeds allocated buffer boundaries.
The technical implementation of this vulnerability involves the improper handling of function index name retrieval operations within the WebAssembly binary parsing pipeline. When the wasm-opt tool processes maliciously crafted WebAssembly binary files, the getFunctionIndexName function attempts to read memory locations beyond the intended buffer boundaries. This over-read condition results in segmentation faults that crash the application process, effectively enabling a denial-of-service attack vector. The flaw is particularly concerning because WebAssembly binary modules can be embedded in various web applications and server-side environments, making the attack surface broad and potentially exploitable through multiple vectors.
The operational impact of CVE-2019-7152 extends beyond simple service disruption, as it can be leveraged in more sophisticated attack scenarios. An attacker could craft malicious WebAssembly modules designed to trigger this buffer over-read condition, potentially causing applications that utilize Binaryen for WebAssembly processing to crash repeatedly. This vulnerability affects not only direct users of wasm-opt but also any system or application that depends on Binaryen for WebAssembly binary format processing, including web browsers with WebAssembly support, server-side WebAssembly runtime environments, and development tools that compile WebAssembly code. The vulnerability aligns with CWE-125, which describes out-of-bounds read conditions, and can be mapped to ATT&CK technique T1059.007 for WebAssembly-based execution and T1499.004 for denial-of-service attacks.
Mitigation strategies for this vulnerability require immediate patching of affected Binaryen versions to 1.38.23 or later, where the buffer over-read has been addressed through proper bounds checking and input validation. Organizations should implement strict input validation for all WebAssembly binary modules processed through Binaryen tools, particularly in environments where untrusted input is expected. Security monitoring should include detection of segmentation fault patterns and process crashes related to WebAssembly processing. Additionally, system administrators should consider implementing sandboxing techniques for WebAssembly execution environments and maintain up-to-date security patches for all WebAssembly-related components in their infrastructure. The vulnerability demonstrates the importance of robust memory safety practices in compiler toolchains and highlights the need for comprehensive testing of edge cases in binary format parsers.