CVE-2013-0875 in FFmpeg
Summary
by MITRE
The ff_add_png_paeth_prediction function in libavcodec/pngdec.c in FFmpeg before 1.1.3 allows remote attackers to have an unspecified impact via a crafted PNG image, related to an out-of-bounds array access.
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Analysis
by VulDB Data Team • 05/05/2021
The vulnerability identified as CVE-2013-0875 represents a critical out-of-bounds array access flaw within the FFmpeg multimedia framework's PNG decoding component. This issue resides in the ff_add_png_paeth_prediction function located in libavcodec/pngdec.c, affecting FFmpeg versions prior to 1.1.3. The vulnerability manifests when processing specially crafted PNG image files that exploit improper bounds checking during the Paeth prediction algorithm implementation. The flaw enables remote attackers to potentially execute arbitrary code or cause denial of service conditions through maliciously constructed PNG files that are processed by applications relying on FFmpeg for multimedia decoding.
The technical nature of this vulnerability aligns with CWE-129, which addresses improper validation of array indices, and specifically demonstrates how inadequate bounds checking can lead to memory corruption issues. The Paeth prediction algorithm is a standard method used in PNG compression for predicting pixel values, but the implementation in FFmpeg fails to properly validate the array access boundaries when processing decoded pixel data. This deficiency allows attackers to craft PNG files that cause the decoder to access memory locations beyond the allocated array boundaries, potentially leading to memory corruption, stack corruption, or heap-based buffer overflows.
The operational impact of this vulnerability extends across numerous applications and systems that utilize FFmpeg for multimedia processing, including media servers, content management systems, web applications, and digital asset management platforms. Attackers can leverage this vulnerability by uploading or transmitting malicious PNG files that trigger the vulnerable code path when the image is decoded or processed. The remote exploitation capability makes this particularly dangerous in web environments where users can upload media files, or in scenarios where applications automatically process external media content. The unspecified impact mentioned in the CVE description suggests that the vulnerability could lead to various outcomes including arbitrary code execution, information disclosure, or system instability depending on the specific memory corruption patterns and the target system configuration.
Mitigation strategies for CVE-2013-0875 primarily focus on immediate version upgrades to FFmpeg 1.1.3 or later, which contain the necessary patches to address the bounds checking deficiencies in the PNG decoding implementation. Organizations should also implement defensive measures such as input validation and sanitization for all uploaded media files, employing content type checking and file format verification before processing. Network-level defenses including web application firewalls and media processing gateways can provide additional layers of protection by filtering suspicious file patterns. The vulnerability also highlights the importance of regular security auditing of multimedia processing libraries and adherence to secure coding practices that emphasize bounds checking, input validation, and memory safety mechanisms. From an ATT&CK framework perspective, this vulnerability maps to techniques involving execution of malicious code through file processing and could be leveraged in initial access or privilege escalation scenarios where multimedia content is processed as part of normal operations. System administrators should also consider implementing monitoring and alerting mechanisms to detect unusual file processing patterns that might indicate exploitation attempts.