CVE-2020-24344 in JerryScript
Summary
by MITRE
JerryScript through 2.3.0 has a (function({a=arguments}){const arguments}) buffer over-read.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 08/14/2020
The vulnerability identified as CVE-2020-24344 resides within JerryScript, a lightweight javascript engine designed for embedded systems and IoT devices. This particular flaw manifests as a buffer over-read condition that occurs during the processing of specific javascript code patterns. The vulnerability affects versions of JerryScript up to and including 2.3.0, making it a significant concern for any system utilizing these engine versions in production environments. The issue stems from improper handling of function parameter destructuring combined with the arguments object, creating a scenario where memory beyond allocated buffers is accessed.
The technical implementation of this vulnerability involves a specific code pattern where a function parameter uses destructuring with a default value assignment to the arguments object. When JerryScript processes code such as function({a=arguments}){const arguments}, the engine fails to properly validate memory boundaries during the parsing and execution phases. This results in the engine attempting to read memory locations that extend beyond the intended buffer boundaries, potentially exposing sensitive data or causing unpredictable behavior. The flaw operates at the interpreter level where the engine's internal memory management fails to account for the complex interaction between parameter destructuring and the reserved arguments identifier.
From an operational perspective, this vulnerability presents a substantial risk to embedded systems and IoT devices that rely on JerryScript for javascript execution. The buffer over-read could potentially allow attackers to extract information from adjacent memory locations, which might contain sensitive data such as encryption keys, user credentials, or system configuration details. The impact extends beyond simple information disclosure as the over-read could also lead to denial of service conditions or potentially enable more sophisticated attacks if combined with other vulnerabilities. The nature of embedded systems makes these devices particularly susceptible since they often lack robust memory protection mechanisms found in desktop environments.
The vulnerability aligns with CWE-125, which describes out-of-bounds read conditions, and demonstrates how improper handling of parameter destructuring in javascript engines can create memory safety issues. From an attack perspective, this flaw fits within the ATT&CK framework's technique T1059.007 for command and scripting interpreter, specifically targeting the javascript interpreter component. The attack surface is particularly concerning for IoT ecosystems where devices may be remotely accessible and where JerryScript is used for application logic execution. Organizations should consider this vulnerability as part of a broader security assessment for embedded systems, particularly those handling sensitive operations or connected to networks.
Mitigation strategies for CVE-2020-24344 primarily involve upgrading to JerryScript version 2.3.1 or later, where the buffer over-read issue has been resolved through improved memory boundary checking. System administrators should also implement runtime monitoring to detect anomalous memory access patterns that might indicate exploitation attempts. Additionally, code review processes should be enhanced to identify and avoid problematic destructuring patterns that could trigger similar issues in other javascript implementations. Organizations using JerryScript in production environments should conduct comprehensive vulnerability assessments to ensure all embedded devices are updated and that appropriate network segmentation is implemented to limit potential attack vectors.