CVE-2015-8663 in FFmpeg
Summary
by MITRE
The ff_get_buffer function in libavcodec/utils.c in FFmpeg before 2.8.4 preserves width and height values after a failure, which allows remote attackers to cause a denial of service (out-of-bounds array access) or possibly have unspecified other impact via a crafted .mov file.
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Analysis
by VulDB Data Team • 07/01/2022
The vulnerability identified as CVE-2015-8663 resides within the FFmpeg multimedia framework, specifically in the ff_get_buffer function located in libavcodec/utils.c. This flaw represents a critical buffer management issue that affects versions prior to 2.8.4, making it a significant concern for systems that process multimedia content. The vulnerability manifests when the function fails to properly handle error conditions during buffer allocation, leading to improper state management that can be exploited by malicious actors.
The technical implementation of this vulnerability stems from the function's failure to reset or properly validate width and height parameters when buffer allocation encounters an error condition. During normal operation, FFmpeg processes multimedia files by allocating buffers based on frame dimensions specified in the file headers. However, when the ff_get_buffer function encounters a failure during this process, it retains the previous width and height values instead of resetting them to safe default states. This behavior creates a dangerous scenario where subsequent processing operations attempt to access arrays using invalid dimensions, resulting in out-of-bounds memory access patterns that can trigger segmentation faults or other undefined behaviors.
The operational impact of this vulnerability extends beyond simple denial of service conditions, as it can potentially enable more severe consequences including arbitrary code execution or system instability. Remote attackers can craft specially malformed .mov files that exploit this weakness by manipulating the file headers to trigger the erroneous buffer handling path. When a vulnerable FFmpeg implementation processes such a crafted file, the preservation of invalid dimension values leads to memory corruption that can be leveraged for privilege escalation or system compromise. The vulnerability affects any system that relies on FFmpeg for multimedia processing, including content delivery networks, media servers, and applications that handle user-uploaded video content.
This vulnerability aligns with CWE-125, which describes out-of-bounds read conditions, and demonstrates characteristics consistent with the ATT&CK technique T1059.007 for command and scripting interpreter. The flaw represents a classic buffer management error that can be exploited through file-based attacks, making it particularly dangerous in environments where users can upload multimedia content. Organizations using FFmpeg versions prior to 2.8.4 should immediately implement mitigations including updating to patched versions, implementing strict input validation, and deploying sandboxing mechanisms to isolate multimedia processing operations. The vulnerability also highlights the importance of proper error handling in multimedia frameworks and underscores the need for comprehensive security testing of media processing libraries to prevent similar issues in the future.