CVE-2007-1001 in PHP
Summary
by MITRE
Multiple integer overflows in the (1) createwbmp and (2) readwbmp functions in wbmp.c in the GD library (libgd) in PHP 4.0.0 through 4.4.6 and 5.0.0 through 5.2.1 allow context-dependent attackers to execute arbitrary code via Wireless Bitmap (WBMP) images with large width or height values.
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Analysis
by VulDB Data Team • 04/07/2025
The vulnerability identified as CVE-2007-1001 represents a critical security flaw within the GD library component of PHP, specifically affecting versions ranging from 4.0.0 through 4.4.6 and 5.0.0 through 5.2.1. This issue manifests in two distinct functions within the wbmp.c file namely createwbmp and readwbmp which handle Wireless Bitmap image processing operations. The flaw stems from improper input validation and arithmetic handling when processing image dimensions, creating conditions where integer overflow can occur during width or height parameter calculations. These functions are particularly concerning as they form part of PHP's image processing capabilities, which are frequently utilized in web applications for generating and manipulating graphics, making them prime targets for exploitation in web-based attack scenarios.
The technical nature of this vulnerability falls under the CWE-190 category of Integer Overflow or Wraparound, which occurs when an integer calculation produces a result that exceeds the maximum value that can be represented by the data type. In this specific case, the integer overflows happen during the processing of WBMP image parameters where attackers can craft malicious image files containing oversized width or height values. When the GD library attempts to allocate memory or perform calculations based on these malformed parameters, the integer arithmetic wraps around to produce unexpectedly small or negative values, leading to buffer overflows or memory corruption conditions. The context-dependent nature of this vulnerability means that exploitation requires specific conditions where the vulnerable PHP application processes user-supplied WBMP images, typically through file upload mechanisms or image processing functions that accept external image data.
The operational impact of CVE-2007-1001 is significant as it allows remote attackers to achieve arbitrary code execution on vulnerable systems, potentially leading to complete system compromise. When exploited successfully, this vulnerability can enable attackers to execute malicious code with the privileges of the web server process, which typically runs with elevated permissions on the hosting system. The attack vector involves uploading or providing malicious WBMP images to PHP applications that utilize the affected GD library functions, making it particularly dangerous in web environments where user uploads are permitted. The vulnerability affects the core image processing functionality of PHP applications, which are widely deployed across the internet for various purposes including content management systems, web applications, and image processing services. This widespread usage means that a single unpatched system could be exploited to gain unauthorized access to sensitive data or to establish persistent backdoors within the compromised environment.
Mitigation strategies for CVE-2007-1001 primarily involve immediate patching of affected PHP installations to versions that contain fixes for the integer overflow conditions in the GD library. Organizations should prioritize updating their PHP environments to versions that have been patched against this vulnerability, typically PHP 5.2.2 or later for the 5.x series and PHP 4.4.7 or later for the 4.x series. Additionally, implementing input validation measures at the application level can provide defense-in-depth protection by sanitizing image parameters before they reach the vulnerable library functions. Security configurations should restrict file upload capabilities and validate all image dimensions against reasonable limits to prevent exploitation attempts. Network-level mitigations include implementing web application firewalls that can detect and block suspicious image file patterns, while system-level hardening measures such as disabling unnecessary image processing functions and implementing strict memory limits for PHP processes can reduce the potential impact of successful exploitation attempts. The vulnerability also highlights the importance of regular security assessments and keeping all third-party libraries updated, as this issue demonstrates how flaws in core library components can affect numerous applications across different platforms and technologies.