CVE-2013-7226 in PHP
Summary
by MITRE
Integer overflow in the gdImageCrop function in ext/gd/gd.c in PHP 5.5.x before 5.5.9 allows remote attackers to cause a denial of service (application crash) or possibly have unspecified other impact via an imagecrop function call with a large x dimension value, leading to a heap-based buffer overflow.
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Analysis
by VulDB Data Team • 06/09/2021
The vulnerability identified as CVE-2013-7226 represents a critical integer overflow flaw within PHP's graphics processing library, specifically affecting versions 5.5.x prior to 5.5.9. This issue resides in the gdImageCrop function located in ext/gd/gd.c, which forms part of PHP's core image manipulation capabilities. The vulnerability manifests when the imagecrop function processes image data with excessively large x dimension values, creating a dangerous condition that can be exploited by remote attackers to compromise system stability and potentially execute arbitrary code.
The technical implementation of this vulnerability stems from inadequate input validation within the gdImageCrop function where integer overflow occurs during dimension calculations. When an attacker supplies a large x dimension value, the arithmetic operations involved in calculating buffer sizes fail to properly handle the overflow condition, resulting in a heap-based buffer overflow. This memory corruption vulnerability operates at the intersection of software security and memory management, where the flaw allows attackers to manipulate memory layout and potentially control program execution flow. The vulnerability aligns with CWE-190, which specifically addresses integer overflow conditions that can lead to buffer overflows, and demonstrates how improper integer handling can create severe security implications in image processing applications.
The operational impact of CVE-2013-7226 extends beyond simple denial of service, presenting attackers with potential paths to system compromise through heap corruption. Remote exploitation allows attackers to cause application crashes that can be leveraged for persistent denial of service attacks against web applications relying on PHP image processing functionality. More concerning is the potential for unspecified other impacts that could include privilege escalation, code execution, or information disclosure, particularly when the vulnerable PHP application processes user-uploaded images. This vulnerability directly affects web applications that utilize the imagecrop function, making it a significant concern for content management systems, file upload portals, and any web service processing image data from untrusted sources.
Mitigation strategies for CVE-2013-7226 require immediate patching of affected PHP installations to versions 5.5.9 or later where the integer overflow has been properly addressed. Organizations should implement comprehensive input validation measures for all image processing functions, including setting strict limits on image dimensions and implementing robust error handling for malformed image data. Security monitoring should be enhanced to detect unusual image processing patterns that might indicate exploitation attempts. The vulnerability demonstrates the importance of secure coding practices in graphics libraries and highlights the need for thorough testing of boundary conditions in mathematical operations. Additionally, implementing web application firewalls and input sanitization layers can provide additional defense-in-depth measures to protect against exploitation attempts targeting this specific vulnerability. The ATT&CK framework categorizes this as a code injection technique through memory corruption, emphasizing the need for proper memory management and input validation in application development practices.