CVE-2013-0846 in FFmpeg
Summary
by MITRE
Array index error in the qdm2_decode_super_block function in libavcodec/qdm2.c in FFmpeg before 1.1 allows remote attackers to have an unspecified impact via crafted QDM2 data, which triggers an out-of-bounds array access.
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Analysis
by VulDB Data Team • 05/17/2021
The vulnerability identified as CVE-2013-0846 represents a critical array index error within the FFmpeg multimedia framework's QDM2 audio decoder implementation. This flaw exists in the qdm2_decode_super_block function located in libavcodec/qdm2.c, where improper bounds checking allows attackers to manipulate array access patterns through specially crafted QDM2 data streams. The issue affects FFmpeg versions prior to 1.1, making it a significant concern for systems that rely on this widely-used multimedia processing library for handling various audio and video formats. The vulnerability demonstrates a classic buffer over-read condition that can potentially lead to arbitrary code execution or system instability when processing maliciously formatted QDM2 content.
The technical nature of this vulnerability aligns with CWE-129, which specifically addresses insufficient checking of array indices, and represents a direct implementation flaw in the audio decoding logic. When the qdm2_decode_super_block function processes malformed QDM2 data, it fails to properly validate the array indices used during super block decoding operations, resulting in out-of-bounds memory access. This type of vulnerability falls under the ATT&CK technique T1203, where adversaries exploit software vulnerabilities to execute arbitrary code, and specifically relates to the use of buffer over-read conditions in multimedia processing components. The flaw occurs during the decoding process when the software attempts to access memory locations beyond the allocated array boundaries, creating potential exploitation vectors for remote attackers.
The operational impact of CVE-2013-0846 extends beyond simple denial-of-service scenarios, as it can potentially enable remote code execution in systems that process untrusted QDM2 content. Attackers can craft malicious QDM2 files that, when processed by vulnerable FFmpeg implementations, trigger the array index error and cause unpredictable behavior including memory corruption, application crashes, or even full system compromise. This vulnerability affects a broad range of applications that depend on FFmpeg for multimedia processing, including media players, content management systems, streaming servers, and security appliances that handle audio/video file processing. The remote attack vector makes this particularly dangerous as it requires no local access and can be exploited through web-based media delivery or file sharing platforms.
Mitigation strategies for CVE-2013-0846 primarily involve immediate patching of FFmpeg installations to versions 1.1 or later where the vulnerability has been resolved through proper array bounds checking implementation. System administrators should also implement network segmentation and content filtering to prevent processing of untrusted QDM2 files, particularly in environments where multimedia content is handled from external sources. Additional protective measures include deploying intrusion detection systems that can identify suspicious QDM2 file patterns and implementing strict input validation for all multimedia processing pipelines. Organizations should also consider using sandboxing techniques and privilege separation when processing multimedia content to limit potential exploitation impacts. The vulnerability serves as a reminder of the critical importance of input validation in multimedia processing libraries and the need for comprehensive security testing of decoding components that handle complex binary formats.