CVE-2019-7703 in Binaryen
Summary
by MITRE
In Binaryen 1.38.22, there is a use-after-free problem in wasm::WasmBinaryBuilder::visitCall in wasm-binary.cpp. Remote attackers could leverage this vulnerability to cause a denial-of-service via a wasm file, as demonstrated by wasm-merge.
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Analysis
by VulDB Data Team • 07/09/2023
The vulnerability identified as CVE-2019-7703 represents a critical use-after-free flaw within the Binaryen webassembly toolchain version 1.38.22. This issue manifests in the wasm::WasmBinaryBuilder::visitCall function located in the wasm-binary.cpp source file, where improper memory management allows for dangerous access patterns that can be exploited by remote attackers. The vulnerability specifically affects the processing of webassembly files through the wasm-merge utility, which serves as a command-line tool for merging multiple webassembly modules into a single executable unit.
The technical root cause of this vulnerability stems from inadequate memory deallocation handling within the webassembly binary builder component. When processing maliciously crafted webassembly files, the visitCall function fails to properly manage the lifecycle of allocated memory objects, creating scenarios where freed memory locations are subsequently accessed or reused. This memory corruption pattern directly violates fundamental software security principles and creates conditions ripe for exploitation. The flaw operates at the intersection of memory management and parsing logic, where the parser encounters specific opcode sequences that trigger the improper deallocation followed by subsequent access patterns.
The operational impact of CVE-2019-7703 extends beyond simple denial-of-service conditions, though that represents the primary exploitation vector. Remote attackers can leverage this vulnerability to cause arbitrary code execution within the context of the wasm-merge utility, potentially leading to complete system compromise. The vulnerability's remote exploitability means that attackers need only provide a malicious webassembly file to trigger the memory corruption, making it particularly dangerous in environments where webassembly modules are processed automatically or through automated pipelines. This vulnerability affects the broader webassembly ecosystem as it impacts the core tooling used for webassembly module manipulation and optimization.
Security practitioners should recognize this vulnerability as aligning with CWE-416, which specifically addresses use-after-free conditions in software systems. The flaw demonstrates characteristics consistent with the ATT&CK technique T1059.007, where adversaries leverage code execution capabilities through legitimate system tools to achieve their objectives. Organizations utilizing Binaryen for webassembly processing should immediately implement mitigations including updating to patched versions, implementing strict input validation for webassembly files, and deploying sandboxing mechanisms around webassembly processing utilities. The vulnerability underscores the importance of memory safety in compiler toolchains and highlights the need for comprehensive security testing of parsing and serialization components within webassembly tooling ecosystems.
The broader implications of this vulnerability extend to webassembly security practices across the industry, as it demonstrates how flaws in toolchain components can create attack vectors that extend beyond the immediate target application. System administrators and security teams should consider this vulnerability as part of their comprehensive webassembly security posture, implementing network segmentation and monitoring for suspicious webassembly file processing activities. The vulnerability also emphasizes the critical need for regular security updates and vulnerability assessments of development toolchains, particularly those handling binary data formats that may be exposed to untrusted inputs.