CVE-2020-23302 in JerryScript
Summary
by MITRE • 06/11/2021
There is a heap-use-after-free at ecma-helpers-string.c:772 in ecma_ref_ecma_string in JerryScript 2.2.0
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Analysis
by VulDB Data Team • 06/13/2021
The vulnerability identified as CVE-2020-23302 represents a critical heap-use-after-free issue within the JerryScript JavaScript engine version 2.2.0. This flaw occurs in the ecma-helpers-string.c source file at line 772 within the ecma_ref_ecma_string function, demonstrating a classic memory safety vulnerability that can lead to arbitrary code execution or system compromise. The issue arises from improper memory management practices where a heap-allocated memory region is accessed after it has been freed, creating a potential attack vector for malicious actors.
The technical implementation of this vulnerability stems from the JavaScript engine's handling of string references and memory allocation patterns. When processing certain JavaScript operations involving string manipulation, the JerryScript engine fails to properly track the lifecycle of ecma_string objects, leading to scenarios where memory addresses are reused before all references to them are properly invalidated. This memory management error manifests as a heap-use-after-free condition, where subsequent operations attempt to access memory that has already been deallocated. The vulnerability is particularly concerning because it occurs within core string handling functionality that is extensively used in JavaScript applications, making exploitation relatively straightforward for attackers who can craft malicious JavaScript payloads.
The operational impact of this vulnerability extends beyond simple memory corruption, as it can enable remote code execution when the affected JavaScript engine is used in web browsers, embedded systems, or IoT devices. Attackers can leverage this flaw to execute arbitrary code with the privileges of the affected application, potentially leading to complete system compromise. The vulnerability's presence in JerryScript 2.2.0 means that any system or application utilizing this JavaScript engine version is at risk, including embedded devices, smart home systems, and web applications that rely on JerryScript for server-side or client-side JavaScript processing. This represents a significant concern for organizations deploying IoT devices or embedded systems where JerryScript is used as the JavaScript interpreter.
Mitigation strategies for CVE-2020-23302 must focus on immediate patching of the JerryScript engine to version 2.3.0 or later, which contains the necessary memory management fixes. Organizations should also implement runtime protections such as address space layout randomization, stack canaries, and heap integrity checks to reduce the effectiveness of exploitation attempts. Additionally, input validation and sanitization measures should be strengthened to prevent malicious JavaScript code from reaching the vulnerable code paths. From a compliance perspective, this vulnerability aligns with CWE-416, which specifically addresses use-after-free conditions, and may be categorized under ATT&CK technique T1059.007 for JavaScript execution. The vulnerability underscores the importance of maintaining up-to-date software components and implementing robust memory safety practices in embedded systems and JavaScript engine implementations to prevent similar issues in future deployments.