CVE-2009-0040 in Firefox
Summary
by MITRE
The PNG reference library (aka libpng) before 1.0.43, and 1.2.x before 1.2.35, as used in pngcrush and other applications, allows context-dependent attackers to cause a denial of service (application crash) or possibly execute arbitrary code via a crafted PNG file that triggers a free of an uninitialized pointer in (1) the png_read_png function, (2) pCAL chunk handling, or (3) setup of 16-bit gamma tables.
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Analysis
by VulDB Data Team • 12/30/2024
The vulnerability identified as CVE-2009-0040 represents a critical security flaw within the libpng reference library implementation that affects versions prior to 1.0.43 and 1.2.35. This issue manifests through improper memory management during PNG file processing, specifically when handling malformed image data that exploits uninitialized pointer dereference conditions. The vulnerability impacts numerous applications that rely on libpng for image processing, including pngcrush and other multimedia tools that parse PNG format files. The flaw operates at the intersection of memory safety and image parsing, creating a scenario where crafted malicious PNG files can trigger unpredictable behavior in affected systems.
The technical exploitation of this vulnerability occurs through three distinct code paths within the libpng library. The first path involves the png_read_png function where an uninitialized pointer is freed during normal image processing operations. The second path exploits pCAL chunk handling, which represents a specific PNG metadata section that can contain malformed data structures. The third path involves the setup of 16-bit gamma tables during color space conversion processes. All three attack vectors leverage the same underlying memory safety issue where pointers are not properly initialized before being dereferenced, creating opportunities for both denial of service and potential code execution scenarios. This vulnerability aligns with CWE-476, which specifically addresses null pointer dereference conditions, and represents a classic example of improper initialization leading to memory corruption.
The operational impact of CVE-2009-0040 extends beyond simple application crashes to potentially enable remote code execution in vulnerable environments. When an application processes a maliciously crafted PNG file, the uninitialized pointer dereference can cause the application to crash or, in more sophisticated exploitation scenarios, allow attackers to execute arbitrary code with the privileges of the affected process. This makes the vulnerability particularly dangerous in web applications, content management systems, or any environment where users can upload or process PNG images. The vulnerability affects both the 1.0.x and 1.2.x release branches of libpng, indicating a widespread impact across different library versions. The attack surface is broad since PNG format is widely used across various platforms and applications, making this vulnerability particularly impactful in enterprise environments where multiple applications depend on the same underlying library.
Mitigation strategies for CVE-2009-0040 primarily focus on immediate library upgrades to versions 1.0.43 or 1.2.35 and later, which contain the necessary fixes for the uninitialized pointer dereference issues. Organizations should implement comprehensive patch management procedures to ensure all affected applications are updated promptly, particularly those handling user-uploaded content. Additionally, input validation measures should be enhanced to include PNG file format verification before processing, and applications should implement proper error handling for malformed image data. Security monitoring should include detection of PNG file processing activities and anomalous memory usage patterns that might indicate exploitation attempts. The vulnerability demonstrates the critical importance of maintaining up-to-date third-party libraries and implementing robust input sanitization practices as recommended by the ATT&CK framework's defense in depth principles, particularly in the context of application security and memory corruption attacks.