CVE-2015-8365 in FFmpeg
Summary
by MITRE
The smka_decode_frame function in libavcodec/smacker.c in FFmpeg before 2.6.5, 2.7.x before 2.7.3, and 2.8.x through 2.8.2 does not verify that the data size is consistent with the number of channels, which allows remote attackers to cause a denial of service (out-of-bounds array access) or possibly have unspecified other impact via crafted Smacker data.
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Analysis
by VulDB Data Team • 06/28/2022
The vulnerability identified as CVE-2015-8365 represents a critical buffer overflow flaw within the FFmpeg multimedia framework's Smacker video decoding implementation. This issue specifically affects the smka_decode_frame function located in libavcodec/smacker.c, where the software fails to validate the consistency between data size and channel count parameters in Smacker format files. The flaw exists across multiple FFmpeg versions including those before 2.6.5, 2.7.x before 2.7.3, and 2.8.x through 2.8.2, making it a widespread concern affecting numerous systems that process multimedia content.
The technical nature of this vulnerability stems from inadequate input validation within the audio decoding process of Smacker files, which are a proprietary video format developed by RAD Game Tools. When the smka_decode_frame function processes crafted Smacker data, it does not properly verify that the allocated buffer size aligns with the expected number of audio channels specified in the file header. This mismatch allows attackers to construct malicious Smacker files that trigger out-of-bounds array access conditions, potentially leading to memory corruption and system instability. The vulnerability operates at the intersection of CWE-129, which addresses insufficient input validation, and CWE-787, concerning out-of-bounds write operations, making it particularly dangerous in multimedia processing environments.
The operational impact of this vulnerability extends beyond simple denial of service scenarios to potentially enable more severe consequences including arbitrary code execution. Remote attackers can exploit this weakness by delivering specially crafted Smacker files through various attack vectors such as email attachments, web downloads, or malicious websites. When vulnerable applications process these files, the out-of-bounds memory access can cause application crashes, system hangs, or in more sophisticated attacks, could be leveraged to execute malicious code with the privileges of the affected application. This makes the vulnerability particularly concerning for web servers, media processing applications, and any system that automatically processes user-uploaded multimedia content without proper sanitization.
Mitigation strategies for CVE-2015-8365 primarily focus on immediate software updates to patched versions of FFmpeg where the input validation has been corrected. Organizations should prioritize patching all systems running vulnerable FFmpeg versions, particularly those handling untrusted multimedia content. Additional defensive measures include implementing strict content filtering mechanisms that validate file formats before processing, deploying network-based intrusion detection systems to monitor for suspicious Smacker file patterns, and establishing robust input validation routines that enforce proper data size channel consistency checks. The ATT&CK framework categorizes this vulnerability under T1203, which covers exploitation for privilege escalation, and T1499, concerning network denial of service attacks, highlighting the multi-faceted nature of the threat landscape this vulnerability creates. System administrators should also consider implementing sandboxing techniques for multimedia processing to contain potential exploitation attempts and establish monitoring protocols to detect unusual memory access patterns that may indicate exploitation attempts.