CVE-2015-8808 in GraphicsMagick
Summary
by MITRE
The DecodeImage function in coders/gif.c in GraphicsMagick 1.3.18 allows remote attackers to cause a denial of service (uninitialized memory access) via a crafted GIF file.
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Analysis
by VulDB Data Team • 09/02/2022
The vulnerability identified as CVE-2015-8808 resides within the GraphicsMagick library's GIF image decoding functionality, specifically in the DecodeImage function located in coders/gif.c. This issue represents a classic case of uninitialized memory access that can be exploited by remote attackers through the careful crafting of malicious GIF files. GraphicsMagick, a robust image processing library widely used in web applications, server environments, and content management systems, becomes vulnerable when processing untrusted image input. The flaw manifests when the library attempts to decode specially constructed GIF files that contain malformed data structures, leading to unpredictable behavior during memory operations.
The technical root cause of this vulnerability stems from insufficient input validation and memory initialization within the GIF decoding pipeline. When GraphicsMagick encounters a crafted GIF file, the DecodeImage function fails to properly initialize memory variables before utilizing them in subsequent processing steps. This uninitialized memory access creates a condition where the application may read from memory locations containing arbitrary data, potentially leading to application crashes, memory corruption, or in some cases, information disclosure. The vulnerability is particularly concerning because it operates at the image parsing level, meaning any application that relies on GraphicsMagick for image handling becomes susceptible to this denial of service attack. The flaw aligns with CWE-457: Use of uninitialized variable, which is categorized under the broader class of memory safety issues in software development.
From an operational perspective, this vulnerability presents a significant risk to web applications, content management systems, and any platform that processes user-uploaded GIF images. Attackers can exploit this weakness by uploading or providing a specially crafted GIF file that triggers the uninitialized memory access during the decoding process. The resulting denial of service impacts system availability and can be leveraged in distributed denial of service attacks where multiple vulnerable systems are targeted simultaneously. The attack vector is particularly dangerous because it requires minimal privileges and can be executed through standard web interactions, making it accessible to attackers with basic technical skills. Organizations using GraphicsMagick in their infrastructure face potential service disruption, application instability, and increased operational overhead as they work to mitigate the vulnerability.
Mitigation strategies for CVE-2015-8808 should focus on both immediate patching and defensive measures. The primary solution involves upgrading to GraphicsMagick version 1.3.23 or later, where the uninitialized memory access issue has been resolved through proper memory initialization and input validation. System administrators should also implement input validation at multiple layers, including image format checking, size limitations, and content sanitization before any processing occurs. Network-level defenses such as web application firewalls and content inspection systems can help identify and block suspicious GIF file patterns. Additionally, implementing proper error handling and graceful degradation mechanisms ensures that even if a malicious GIF file is processed, the system maintains operational stability. The vulnerability demonstrates the importance of following security best practices such as those outlined in the OWASP Top Ten and NIST guidelines for secure coding, particularly regarding memory management and input validation. Organizations should also consider implementing automated vulnerability scanning and regular security assessments to identify similar issues in other third-party libraries and dependencies that may be present in their software stacks.