CVE-2012-0848 in FFmpeg
Summary
by MITRE
Heap-based buffer overflow in the ws_snd_decode_frame function in libavcodec/ws-snd1.c in FFmpeg 0.9.1 allows remote attackers to cause a denial of service (application crash) via a crafted media file, related to an incorrect calculation, aka "wrong samples count."
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Analysis
by VulDB Data Team • 12/12/2021
The vulnerability identified as CVE-2012-0848 represents a critical heap-based buffer overflow in the FFmpeg multimedia framework version 0.9.1. This flaw exists within the ws_snd_decode_frame function located in the libavcodec/ws-snd1.c file, which processes ws-snd1 audio format files. The vulnerability arises from an incorrect calculation of samples count during the decoding process, creating a condition where maliciously crafted media files can trigger memory corruption. The issue falls under the Common Weakness Enumeration category CWE-121, which describes heap-based buffer overflow conditions where insufficient bounds checking allows attackers to write beyond allocated memory boundaries. This particular vulnerability demonstrates how improper input validation can lead to memory corruption in multimedia processing libraries that handle various audio formats.
The technical exploitation of this vulnerability occurs when FFmpeg processes a specially crafted media file containing malformed ws-snd1 audio data. During the decoding process, the ws_snd_decode_frame function calculates the number of audio samples to be processed but fails to properly validate or constrain this calculation. When an attacker provides a media file with incorrect sample count values, the function attempts to allocate heap memory based on these malformed values, resulting in a buffer overflow condition. The overflow occurs in the heap memory region where audio sample data is stored, potentially overwriting adjacent memory structures or metadata. This type of vulnerability is particularly dangerous because it can be triggered through normal media playback operations without requiring special privileges or complex attack vectors, making it accessible to remote attackers who can simply distribute malicious media files.
The operational impact of CVE-2012-0848 extends beyond simple denial of service to potentially enable more sophisticated attacks. While the immediate effect manifests as application crashes and system instability, the heap-based nature of the overflow creates opportunities for more advanced exploitation techniques. Attackers could potentially leverage this vulnerability to execute arbitrary code through carefully crafted payloads that overwrite function pointers or return addresses in the heap memory. The vulnerability affects any system running FFmpeg 0.9.1 or earlier versions, including web servers, media processing applications, and consumer software that utilizes FFmpeg for multimedia handling. This makes it particularly concerning for server environments where media file processing is common, as attackers could use this vulnerability to compromise entire systems through media file uploads or streaming services.
Mitigation strategies for CVE-2012-0848 primarily focus on upgrading to patched versions of FFmpeg where the buffer overflow has been corrected through proper bounds checking and input validation. System administrators should immediately update their FFmpeg installations to version 0.9.2 or later, which includes fixes for this vulnerability. Additionally, implementing proper input validation at the application level can provide defense-in-depth measures, where applications using FFmpeg can validate media file headers before processing. Network-based protections such as content filtering and media file scanning can help prevent malicious files from reaching vulnerable systems. The vulnerability also highlights the importance of using memory-safe programming practices and implementing address space layout randomization as part of overall system hardening. Organizations should also consider implementing sandboxing techniques for media processing components to limit the potential impact of successful exploitation attempts. According to ATT&CK framework, this vulnerability maps to T1203 - Exploitation for Client Execution and T1499 - Endpoint Termination, as it enables remote code execution and system instability through media file processing.