CVE-2011-0524 in gypsy
Summary
by MITRE
Multiple buffer overflows in the NMEA parser (nmea-gen.c) in gypsy 0.8 allow local users to cause a denial of service (crash) via unspecified vectors related to the sprintf function.
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Analysis
by VulDB Data Team • 12/07/2021
The vulnerability identified as CVE-2011-0524 resides within the gypsy 0.8 software suite, specifically within the NMEA parser component known as nmea-gen.c. This represents a critical security flaw that affects the proper handling of input data from Global Positioning System (GPS) devices that communicate using the NMEA 0183 protocol. The NMEA parser is responsible for interpreting and processing GPS data streams that contain positional information, speed data, and other navigation-related metrics. When gypsy processes malformed or excessively long NMEA sentences, the vulnerability manifests as multiple buffer overflow conditions that can be exploited by local users to disrupt system operations.
The technical implementation of this vulnerability stems from improper bounds checking within the sprintf function usage within the nmea-gen.c file. Buffer overflows occur when more data is written to a fixed-size memory buffer than it can accommodate, causing adjacent memory locations to be overwritten. In this case, the sprintf function is likely used to format and store incoming GPS data without adequate validation of input length or buffer boundaries. The vulnerability is particularly concerning because it allows local users to trigger crashes through unspecified vectors, meaning the exact attack paths are not fully documented but can be inferred from the nature of buffer overflows in string manipulation functions. The sprintf function's behavior when handling format specifiers and input data that exceeds allocated buffer space creates conditions where memory corruption occurs, leading to application instability and potential system crashes.
The operational impact of this vulnerability extends beyond simple denial of service, as local attackers can leverage these buffer overflows to cause system instability that may affect other running processes or even compromise system integrity. When the gypsy application crashes due to these buffer overflows, it can disrupt GPS-based applications that depend on accurate positioning data, potentially affecting navigation systems, tracking services, or any software that relies on GPS information. The local nature of the attack means that an attacker must already have access to the system, but this still represents a significant risk in environments where multiple users have access to the same machine or where privilege escalation attacks might be possible. The vulnerability also demonstrates poor input validation practices in the software development lifecycle, indicating that the application may be susceptible to other similar issues throughout its codebase.
Mitigation strategies for CVE-2011-0524 should focus on immediate code-level fixes that address the buffer overflow conditions in the NMEA parser. The most effective approach involves implementing proper bounds checking before any sprintf operations, ensuring that input data lengths are validated against buffer sizes and that appropriate error handling is implemented. Software developers should replace vulnerable sprintf calls with safer alternatives such as snprintf or vsnprintf that allow for explicit buffer size specification, thereby preventing buffer overflows from occurring. Additionally, input validation should be enhanced to properly handle malformed NMEA sentences and reject data that exceeds expected length parameters. System administrators should consider applying patches or updates to gypsy 0.8, or if that is not possible, implementing runtime protections such as stack canaries or address space layout randomization. The vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and may also relate to CWE-122, heap-based buffer overflow, depending on memory allocation patterns. From an adversarial perspective, this vulnerability could be categorized under ATT&CK technique T1499.004 for network denial of service and potentially T1068 for local privilege escalation if the application runs with elevated privileges. Organizations should also consider implementing monitoring solutions to detect abnormal application behavior or crashes that may indicate exploitation attempts.