CVE-2023-49551 in MJS
Summary
by MITRE • 01/03/2024
An issue in Cesanta mjs 2.20.0 allows a remote attacker to cause a denial of service via the mjs_op_json_parse function in the msj.c file.
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Analysis
by VulDB Data Team • 09/06/2024
The vulnerability identified as CVE-2023-49551 affects Cesanta mjs version 2.20.0, a lightweight JavaScript engine designed for embedded systems and IoT devices. This remote denial of service flaw resides within the mjs_op_json_parse function located in the msj.c source file, representing a critical security weakness that can be exploited by unauthorized attackers without requiring authentication or specialized privileges. The mjs JavaScript engine is commonly utilized in resource-constrained environments where efficient parsing of JSON data is essential for device communication and data processing operations.
The technical implementation flaw manifests when the mjs_op_json_parse function processes malformed or specially crafted JSON input data. This function serves as the core component responsible for parsing JSON formatted strings into JavaScript objects within the mjs runtime environment. When confronted with specific patterns of malformed input, the parsing function fails to properly validate or handle edge cases, leading to unpredictable behavior that ultimately results in system resource exhaustion or complete application termination. The vulnerability stems from insufficient input validation mechanisms within the JSON parsing logic, allowing attackers to craft malicious payloads that trigger memory corruption or infinite loop conditions during the parsing process.
The operational impact of this vulnerability extends beyond simple service disruption, potentially affecting the reliability and availability of embedded systems that depend on the mjs JavaScript engine for their core functionality. Devices utilizing this engine for web server operations, data processing tasks, or communication protocols become susceptible to remote exploitation where attackers can remotely initiate denial of service conditions. The vulnerability affects systems ranging from IoT devices and embedded routers to industrial control systems and smart home appliances that incorporate Cesanta mjs as their scripting engine. Given the widespread adoption of mjs in embedded environments, the potential attack surface is extensive, with numerous devices across various industries at risk of being compromised through this remote denial of service vector.
Security professionals should consider this vulnerability in the context of the Common Weakness Enumeration framework, where it aligns with CWE-400, which describes "Uncontrolled Resource Consumption" or "Resource Exhaustion" conditions that occur when applications fail to properly manage system resources. The ATT&CK framework categorizes this as a denial of service attack pattern under the T1499.004 sub-technique, specifically "Network Denial of Service," where adversaries leverage vulnerabilities in network services to disrupt availability. Organizations should implement immediate mitigations including updating to patched versions of Cesanta mjs, implementing network segmentation to limit exposure, and deploying intrusion detection systems to monitor for exploitation attempts. Additionally, input validation measures and rate limiting mechanisms should be considered as defensive strategies to reduce the attack surface and prevent successful exploitation of this vulnerability.