CVE-2018-11596 in Espruino
Summary
by MITRE
Espruino before 1.99 allows attackers to cause a denial of service (application crash) with a user crafted input file via a Buffer Overflow during syntax parsing because a check for '\0' is made for the wrong array element in jsvar.c.
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Analysis
by VulDB Data Team • 03/19/2023
The vulnerability identified as CVE-2018-11596 affects Espruino versions prior to 1.99 and represents a critical buffer overflow condition that can be exploited to cause application crashes and denial of service. This issue stems from improper input validation during syntax parsing operations within the JavaScript interpreter component of the Espruino platform. The vulnerability specifically manifests when the system processes user-crafted input files that contain maliciously constructed data patterns, leading to unpredictable application behavior and potential system instability.
The technical flaw resides in the jsvar.c source file where a critical boundary check is performed against an incorrect array element during the parsing process. This misalignment in validation logic creates a scenario where an attacker can craft input that bypasses normal safety mechanisms, allowing malicious data to overflow allocated memory buffers. The vulnerability is particularly dangerous because it operates at the parsing layer, meaning that any JavaScript code submitted to the Espruino interpreter could potentially trigger this condition. The specific check for null termination character '' is executed against the wrong memory location, effectively rendering the protective mechanism useless and enabling unauthorized memory manipulation.
The operational impact of this vulnerability extends beyond simple application instability to encompass potential system compromise and service disruption. When exploited, the buffer overflow can cause the Espruino interpreter to crash, requiring system restart and potentially leading to data loss or service unavailability. This affects embedded systems and IoT devices that rely on Espruino for JavaScript execution, making it particularly concerning for production environments where reliability is paramount. The vulnerability's exploitation requires minimal skill level, as attackers only need to craft a specific input file that triggers the parsing error, making it a significant risk for systems that accept user input without proper sanitization.
From a cybersecurity perspective, this vulnerability aligns with CWE-121, which describes buffer overflow conditions in stack-based buffers, and represents a classic example of improper input validation that can lead to arbitrary code execution. The ATT&CK framework categorizes this as a Denial of Service attack technique, specifically within the system service interruption category. Organizations utilizing Espruino platforms should prioritize immediate patching to version 1.99 or later, which includes the corrected boundary checking logic. Additionally, implementing input validation mechanisms at multiple layers, including runtime checks and sandboxing techniques, can provide additional defense-in-depth measures. Regular security assessments of embedded systems and IoT devices using Espruino should include verification of interpreter versions and proper input sanitization procedures to prevent exploitation of similar vulnerabilities in the future.