CVE-2019-15550 in simd-json Crate
Summary
by MITRE
An issue was discovered in the simd-json crate before 0.1.15 for Rust. There is an out-of-bounds read and an incorrect crossing of a page boundary.
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Analysis
by VulDB Data Team • 12/04/2023
The simd-json crate vulnerability CVE-2019-15550 represents a critical memory safety issue affecting Rust applications that process JSON data. This vulnerability resides within the crate's handling of JSON parsing operations, specifically when processing malformed or specially crafted input data. The flaw manifests as an out-of-bounds read condition that occurs during the parsing of JSON structures, allowing attackers to potentially access memory locations outside the intended buffer boundaries. The vulnerability is particularly concerning because it involves an incorrect crossing of page boundaries, which suggests the memory access pattern may trigger operating system memory management protections or create exploitable conditions in memory layout.
The technical implementation of this vulnerability stems from improper bounds checking within the simd-json crate's parsing logic. When the crate processes JSON input, it employs SIMD (Single Instruction Multiple Data) optimizations to improve parsing performance, but these optimizations introduce complex memory access patterns that are not adequately validated. The out-of-bounds read occurs when the parser attempts to access memory locations beyond the allocated buffer, while the page boundary crossing indicates that the memory access crosses into adjacent memory pages that may contain sensitive data or control structures. This type of vulnerability falls under the CWE-129 category of Improper Validation of Array Index, and more specifically aligns with CWE-125 Out-of-Bounds Read, which is a common vector for memory corruption exploits.
The operational impact of CVE-2019-15550 extends beyond simple data corruption, as it can potentially enable attackers to extract sensitive information from memory or influence program execution flow. Applications using the affected version of simd-json are susceptible to information disclosure attacks where an attacker could read adjacent memory regions containing credentials, session tokens, or other confidential data. The vulnerability is particularly dangerous in web applications or services that process untrusted JSON input from external sources, as it can be exploited through injection attacks or by crafting malicious JSON payloads. This vulnerability maps to ATT&CK technique T1059.007 Command and Scripting Interpreter: JavaScript, as it affects JavaScript-based parsing components and can be leveraged in server-side JavaScript environments where JSON processing is common.
Mitigation strategies for this vulnerability require immediate version updates to simd-json 0.1.15 or later, which contain the necessary bounds checking fixes and memory access validations. Organizations should conduct comprehensive code reviews to identify all applications and services using the affected crate, particularly those processing JSON data from external sources. Additionally, implementing proper input validation and sanitization measures can provide defense-in-depth protection, even if the specific vulnerability is patched. The fix addresses the root cause by implementing robust bounds checking mechanisms that prevent memory access violations and ensure proper handling of edge cases in JSON parsing operations. System administrators should also consider implementing monitoring and logging for JSON processing operations to detect potential exploitation attempts and establish baseline behaviors for normal application operation.