CVE-2007-3475 in GD Graphics Library
Summary
by MITRE
The GD Graphics Library (libgd) before 2.0.35 allows user-assisted remote attackers to cause a denial of service (crash) via a GIF image that has no global color map.
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Analysis
by VulDB Data Team • 07/21/2019
The vulnerability identified as CVE-2007-3475 represents a critical denial of service flaw within the GD Graphics Library, a widely used open-source library for image manipulation in web applications and server-side graphics processing. This vulnerability specifically affects versions of libgd prior to 2.0.35 and stems from inadequate input validation when processing GIF image files. The flaw occurs when the library encounters a GIF image lacking a global color map, which is a fundamental component of the GIF file format that defines the color palette available for rendering the image. This absence triggers a memory access violation or improper handling of the file structure, leading to a crash of the application or service utilizing the library. The vulnerability is classified as user-assisted remote, meaning that an attacker must convince a user to process a malicious GIF file, typically through web-based interactions or file uploads, though the attack can be automated in certain contexts.
The technical implementation of this vulnerability resides in the library's failure to properly validate the structure of GIF files before attempting to parse them. When libgd encounters a GIF image without a global color map, the parsing routine does not adequately check for the presence of required fields or handle the missing data gracefully. This deficiency leads to memory corruption or null pointer dereferences, causing the application to terminate unexpectedly. The vulnerability directly maps to CWE-125, which describes out-of-bounds read conditions, and CWE-248, which covers exposure of an uninitialized variable. The flaw demonstrates poor defensive programming practices where the library fails to implement proper error handling and input sanitization mechanisms that would prevent the crash from occurring. In the context of web applications, this vulnerability can be exploited through file upload mechanisms or image processing pipelines where user-supplied GIF files are processed without proper validation.
The operational impact of CVE-2007-3475 extends beyond simple service disruption to potentially compromise the availability of critical web services and applications that rely on the GD Graphics Library for image processing functionality. Attackers can leverage this vulnerability to systematically crash web servers, content management systems, or any application that processes user-uploaded images using libgd versions before 2.0.35. This denial of service can be particularly devastating in environments where image processing is a core feature, such as social media platforms, e-commerce sites, or image hosting services. The attack can be executed with minimal technical expertise since it only requires crafting a malicious GIF file that lacks a global color map, making it an attractive vector for automated exploitation. From an attacker's perspective, this vulnerability aligns with ATT&CK technique T1499.004, which involves network denial of service attacks, and T1059.007, covering command and scripting interpreters used for exploitation.
Mitigation strategies for this vulnerability center on immediate software updates and comprehensive input validation measures. System administrators should prioritize updating all affected installations of libgd to version 2.0.35 or later, where the parsing logic has been corrected to handle GIF files without global color maps gracefully. Additionally, organizations should implement strict input validation for all image uploads, including MIME type checking, file format validation, and size limitations to prevent exploitation. The implementation of proper error handling and defensive programming practices within applications that utilize libgd can provide additional protection layers against similar vulnerabilities. Organizations should also consider deploying web application firewalls or content filtering solutions that can detect and block suspicious GIF file patterns. Regular security assessments and vulnerability scanning should be conducted to identify other potentially affected components within the application stack that may rely on outdated versions of the GD library, ensuring comprehensive protection against this and similar class of vulnerabilities.