CVE-2013-0844 in FFmpeg
Summary
by MITRE
Off-by-one error in the adpcm_decode_frame function in libavcodec/adpcm.c in FFmpeg before 1.0.4 allows remote attackers to have an unspecified impact via crafted DK4 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-2013-0844 represents a critical off-by-one error within the FFmpeg multimedia framework's audio decoding component. This flaw exists in the adpcm_decode_frame function located in libavcodec/adpcm.c, affecting FFmpeg versions prior to 1.0.4. The vulnerability specifically targets DK4 data format processing, which is a variant of adaptive differential pulse code modulation used in various audio compression schemes. The issue stems from improper bounds checking during the decoding process where the function fails to properly validate array indices against the actual array dimensions, creating a scenario where memory access occurs beyond the allocated buffer boundaries. This type of vulnerability falls under the CWE-129 category of Improper Validation of Array Index, which is classified as a fundamental weakness in software design that allows attackers to manipulate array access patterns. The flaw operates at the intersection of multimedia processing and memory safety, where the decoding routine processes crafted audio data that contains malicious index values designed to trigger the out-of-bounds access condition.
The operational impact of this vulnerability extends beyond simple memory corruption, as it creates potential attack vectors that could lead to arbitrary code execution or system instability. When remote attackers submit specially crafted DK4 audio data to a vulnerable FFmpeg instance, the adpcm_decode_frame function processes the malformed input and attempts to access memory locations that are outside the legitimate array boundaries. This out-of-bounds access can result in several security implications including information disclosure through memory leaks, denial of service through application crashes, or potentially more severe consequences if the memory corruption affects critical system structures. The vulnerability demonstrates how multimedia processing libraries can become attack surfaces when they fail to implement proper input validation and boundary checking mechanisms. The attack scenario typically involves an attacker who can influence the input stream processed by FFmpeg, such as through web browsers, media players, or streaming services that utilize this library, making the vulnerability particularly dangerous in environments where untrusted audio content is processed.
Mitigation strategies for CVE-2013-0844 require immediate version updates to FFmpeg 1.0.4 or later, which contain the necessary patches to correct the off-by-one error in the array boundary checking logic. System administrators should prioritize patching all affected installations, particularly those running media servers, content delivery networks, or any application that processes audio content through FFmpeg. The fix implemented in the patched versions involves strengthening the validation logic within the adpcm_decode_frame function to ensure that all array indices are properly checked against the actual array dimensions before any memory access occurs. Additional defensive measures include implementing input sanitization layers, using memory protection mechanisms such as stack canaries, and deploying intrusion detection systems that monitor for unusual memory access patterns. Organizations should also consider implementing network segmentation and access controls to limit exposure to potential attack vectors that could leverage this vulnerability. The ATT&CK framework categorizes this type of vulnerability under the T1059.007 technique for Command and Scripting Interpreter: PowerShell, as it represents a code execution vulnerability that could be exploited through media processing components. Security monitoring should focus on detecting anomalous behavior in multimedia processing components and ensuring that all third-party libraries are kept current with security patches to prevent exploitation of similar boundary condition vulnerabilities.