CVE-2018-17174 in NMEA Library
Summary
by MITRE
A stack-based buffer overflow was discovered in the xtimor NMEA library (aka nmealib) 0.5.3. nmea_parse() in parser.c allows an attacker to trigger denial of service (even arbitrary code execution in a certain context) in a product using this library via malformed data.
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Analysis
by VulDB Data Team • 03/26/2020
The vulnerability identified as CVE-2018-17174 represents a critical stack-based buffer overflow within the xtimor NMEA library version 0.5.3, specifically affecting the nmea_parse() function located in parser.c. This flaw exposes systems that integrate this library to potential exploitation by malicious actors who can craft malformed NMEA data streams to trigger the vulnerability. The NMEA (National Marine Electronics Association) protocol is widely used for communication between marine electronic devices and is commonly integrated into various navigation, tracking, and monitoring systems across multiple industries including maritime, automotive, and aviation sectors.
The technical implementation of this vulnerability stems from insufficient input validation within the nmea_parse() function, which processes NMEA sentences without adequate bounds checking on buffer allocations. When malformed data is received, the function fails to properly constrain the amount of data copied into stack-allocated buffers, allowing an attacker to overwrite adjacent stack memory locations. This classic buffer overflow condition creates opportunities for arbitrary code execution when the overflowed memory contains return addresses or other critical execution pointers, particularly in environments where the library is used in networked applications or embedded systems with elevated privileges.
The operational impact of this vulnerability extends beyond simple denial of service scenarios, as it can potentially enable remote code execution in contexts where the vulnerable library is integrated into systems with sufficient privileges to execute arbitrary instructions. The vulnerability affects products that utilize the nmealib library for processing GPS and navigation data, which includes maritime navigation systems, vehicle tracking solutions, and various industrial monitoring applications. Attackers can exploit this flaw by injecting maliciously crafted NMEA sentences that cause the stack buffer to overflow, potentially leading to system compromise, data corruption, or complete service disruption.
Systems at risk include any application or device that relies on the xtimor NMEA library for processing navigation data, particularly those deployed in critical infrastructure environments such as shipping vessels, aircraft navigation systems, and industrial automation platforms. The vulnerability is particularly concerning because NMEA data streams are often received from external sources including GPS satellites, terrestrial receivers, and other navigation devices, making it difficult to control input validation. Organizations should prioritize immediate remediation efforts by updating to patched versions of the library, implementing input validation layers, and monitoring for exploitation attempts. Additionally, network segmentation and intrusion detection systems should be deployed to detect and prevent the injection of malformed NMEA data into vulnerable systems. This vulnerability aligns with CWE-121 Stack-based Buffer Overflow and represents a significant risk under ATT&CK framework category T1203 Exploitation for Client Execution, emphasizing the need for comprehensive security measures including regular patch management and input sanitization protocols.
The broader implications of this vulnerability highlight the importance of secure coding practices in embedded systems and third-party library integration. Many organizations fail to adequately test third-party components for security vulnerabilities, particularly in legacy systems where the NMEA protocol has been integrated for years without proper security assessments. The vulnerability demonstrates how seemingly benign protocols like NMEA can become attack vectors when integrated with poorly secured libraries, underscoring the necessity of thorough security reviews during system integration phases. Organizations should implement security testing procedures that include static code analysis, dynamic testing, and vulnerability scanning of all third-party components to prevent similar issues from compromising operational integrity.