CVE-2019-7638 in Simple DirectMedia Layer
Summary
by MITRE
SDL (Simple DirectMedia Layer) through 1.2.15 and 2.x through 2.0.9 has a heap-based buffer over-read in Map1toN in video/SDL_pixels.c.
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Analysis
by VulDB Data Team • 07/09/2023
The vulnerability identified as CVE-2019-7638 represents a critical heap-based buffer over-read flaw within the Simple DirectMedia Layer library, a widely-used cross-platform development library for multimedia applications. This issue affects SDL versions through 1.2.15 and 2.x through 2.0.9, making it a persistent concern for developers and system administrators who rely on this foundational multimedia framework. The vulnerability specifically resides in the Map1toN function located within the video/SDL_pixels.c source file, indicating a deep integration with the library's pixel manipulation and color mapping capabilities. The flaw demonstrates characteristics consistent with CWE-125, which describes out-of-bounds read vulnerabilities that occur when a program reads data past the end of a buffer, potentially exposing sensitive memory contents or causing application instability.
The technical implementation of this vulnerability stems from inadequate bounds checking within the pixel conversion and mapping routines that SDL employs for handling different color formats and pixel data transformations. When applications utilizing SDL process certain image data or perform pixel format conversions, the Map1toN function fails to properly validate array boundaries before accessing memory locations. This over-read condition can lead to the program reading adjacent memory segments that may contain uninitialized data, sensitive information from other processes, or even corrupted program state that could be exploited for arbitrary code execution. The heap-based nature of the vulnerability indicates that the affected memory regions are dynamically allocated and managed by the system's heap allocator, making the exploitation potential more sophisticated and potentially more reliable than stack-based buffer overflows.
The operational impact of CVE-2019-7638 extends across numerous applications and systems that depend on SDL for multimedia functionality, including but not limited to games, multimedia players, and graphics-intensive software. Attackers could potentially leverage this vulnerability to gain unauthorized access to memory contents, leading to information disclosure or system compromise. The vulnerability's presence in both SDL 1.2 and 2.x branches means that a substantial portion of legacy and contemporary applications could be affected, particularly those that process user-supplied image data or perform complex pixel operations. This makes the vulnerability particularly dangerous in environments where applications handle untrusted input, as it could enable remote code execution or privilege escalation attacks.
Mitigation strategies for CVE-2019-7638 primarily involve upgrading to patched versions of SDL where the buffer over-read has been addressed through proper bounds checking and memory validation. Organizations should prioritize updating their SDL dependencies to versions that contain the necessary security fixes, typically SDL 1.2.16 and 2.0.10 or later. Additionally, implementing defensive programming practices such as input validation, memory sanitization, and runtime bounds checking can provide additional layers of protection. Security researchers and developers should consider employing static and dynamic analysis tools to identify similar patterns in their own codebases that might exhibit similar vulnerabilities. The ATT&CK framework categorizes this type of vulnerability under software exploitation techniques, specifically targeting memory corruption vulnerabilities that can lead to arbitrary code execution, making it a significant concern for enterprise security teams responsible for protecting against advanced persistent threats and zero-day exploits.