CVE-2014-9709 in GD
Summary
by MITRE
The GetCode_ function in gd_gif_in.c in GD 2.1.1 and earlier, as used in PHP before 5.5.21 and 5.6.x before 5.6.5, allows remote attackers to cause a denial of service (buffer over-read and application crash) via a crafted GIF image that is improperly handled by the gdImageCreateFromGif function.
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Analysis
by VulDB Data Team • 05/02/2022
The vulnerability described in CVE-2014-9709 represents a critical buffer over-read flaw within the GD graphics library implementation that affects multiple PHP versions. This issue manifests specifically within the GetCode_ function located in the gd_gif_in.c source file, where improper handling of malformed GIF image data leads to memory corruption conditions. The vulnerability impacts GD library versions 2.1.1 and earlier, creating a significant security risk for web applications that process user-uploaded GIF images through PHP's gdImageCreateFromGif function.
The technical exploitation of this vulnerability occurs when a remote attacker crafts a specially malformed GIF image that triggers a buffer over-read condition during the image parsing process. When PHP processes such malicious input through the affected gdImageCreateFromGif function, the GetCode_ function fails to properly validate the GIF data structure, causing the application to read beyond allocated memory boundaries. This memory corruption results in application crashes and potential denial of service conditions that can be exploited to disrupt legitimate service operations. The flaw stems from inadequate bounds checking and input validation within the GIF parsing logic, making it particularly dangerous for web applications that accept arbitrary image uploads.
From an operational perspective, this vulnerability presents a substantial risk to web server availability and system stability. Attackers can leverage this weakness to repeatedly crash web applications that utilize PHP's GD library for image processing, effectively creating a denial of service attack vector. The impact extends beyond simple service disruption as the vulnerability can potentially be chained with other exploits or used to gain further system access through application-level memory corruption. Systems running vulnerable PHP versions before 5.5.21 and 5.6.x before 5.6.5 remain particularly susceptible, as these releases contain the unpatched GD library implementation.
The vulnerability maps directly to CWE-125: Out-of-bounds Read within the Common Weakness Enumeration framework, which categorizes it as a memory safety issue resulting from insufficient input validation. From an attack framework perspective, this flaw aligns with techniques described in the MITRE ATT&CK methodology under the T1499.004 sub-technique for Network Denial of Service, where attackers manipulate application processing to cause system instability. Organizations should implement immediate patching strategies to address this vulnerability, ensuring all PHP installations are updated to versions that include the fixed GD library implementation. Additionally, input validation measures should be enhanced at the application level to prevent processing of malformed image data, and web application firewalls can be configured to detect and block suspicious image upload patterns that might indicate exploitation attempts.