CVE-2012-2785 in FFmpeg
Summary
by MITRE
Multiple unspecified vulnerabilities in libavcodec/wmalosslessdec.c in FFmpeg before 0.11 have unknown impact and attack vectors, related to (1) "some subframes only encode some channels" or (2) a large order value.
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Analysis
by VulDB Data Team • 12/13/2021
The vulnerability identified as CVE-2012-2785 resides within the FFmpeg multimedia framework's libavcodec library, specifically in the wmalosslessdec.c module responsible for decoding WMA Lossless audio streams. This flaw affects FFmpeg versions prior to 0.11 and represents a critical security issue that could potentially allow attackers to exploit the decoding process through malformed input data. The vulnerability's classification as "multiple unspecified vulnerabilities" indicates that the flaw encompasses several related weaknesses within the same code module, making it particularly challenging to fully characterize without detailed technical analysis. The affected component processes Windows Media Audio Lossless format streams, which are commonly used in multimedia applications and digital audio processing environments. The vulnerability's impact is considered unknown due to the lack of specific details about how the flaw manifests in practice, though the potential for arbitrary code execution or system compromise remains a serious concern given the nature of multimedia decoders.
The technical implementation of this vulnerability stems from two primary conditions within the WMA Lossless decoder logic. The first condition involves subframes that only encode certain channels rather than all channels in the audio stream, creating potential for buffer manipulation or memory corruption when the decoder attempts to process inconsistent channel data structures. The second condition relates to large order values that can cause integer overflows or excessive memory allocation during the decoding process. These issues are particularly dangerous because they can lead to memory corruption, stack overflows, or heap-based buffer overflows when the decoder processes malformed WMA Lossless files. The flaw demonstrates poor input validation and inadequate boundary checking within the audio decoding pipeline, where the decoder fails to properly validate the size parameters and channel configurations provided in the encoded stream. This vulnerability is particularly concerning in environments where FFmpeg is used for processing untrusted multimedia content, such as web applications, media servers, or content management systems.
The operational impact of CVE-2012-2785 extends beyond simple denial-of-service scenarios to potentially enable remote code execution in vulnerable systems. When exploited, this vulnerability could allow attackers to execute arbitrary code on systems running affected versions of FFmpeg, particularly in applications that process multimedia content from untrusted sources. The attack vectors are likely to involve crafting specially malformed WMA Lossless files that trigger the memory corruption conditions when processed by the vulnerable decoder. This vulnerability is particularly dangerous in web-based applications or content delivery networks where multimedia files are processed automatically, as attackers could embed malicious payloads within audio files that would execute code when the content is decoded. The vulnerability's impact is amplified by the widespread use of FFmpeg in various multimedia applications, including media players, streaming servers, and content management systems, making it a prime target for exploitation in various attack scenarios. The lack of specific details about the exact attack vectors and impact parameters means that security teams must assume the worst-case scenario and implement defensive measures accordingly.
Mitigation strategies for CVE-2012-2785 should focus on immediate version upgrades to FFmpeg 0.11 or later, which contain patches addressing the identified vulnerabilities in the WMA Lossless decoder. Organizations should also implement input validation controls at network boundaries or application levels to filter out malformed multimedia content before it reaches systems running vulnerable FFmpeg versions. The implementation of sandboxing mechanisms and restricted execution environments can provide additional protection layers when processing untrusted multimedia content. Security teams should also consider implementing network monitoring to detect anomalous behavior that might indicate exploitation attempts, particularly around multimedia processing services. The vulnerability highlights the importance of maintaining up-to-date multimedia libraries and implementing robust input validation practices in applications that process multimedia content. This issue aligns with CWE-129 and CWE-131 categories related to insufficient validation of length fields and improper handling of buffer sizes, respectively. From an ATT&CK perspective, this vulnerability could be leveraged as part of initial access or execution phases, particularly when targeting systems that process multimedia content automatically, and represents a significant risk for privilege escalation and lateral movement in compromised environments.