CVE-2016-6832 in libav
Summary
by MITRE
Heap-based buffer overflow in the ff_audio_resample function in resample.c in libav before 11.4 allows remote attackers to cause a denial of service (crash) via vectors related to buffer resizing.
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Analysis
by VulDB Data Team • 08/15/2020
The vulnerability identified as CVE-2016-6832 represents a critical heap-based buffer overflow within the libav multimedia framework, specifically affecting the ff_audio_resample function in the resample.c file. This flaw exists in libav versions prior to 11.4 and demonstrates a classic memory corruption issue that can be exploited remotely to trigger denial of service conditions. The vulnerability arises from improper handling of buffer resizing operations during audio resampling processes, creating opportunities for attackers to manipulate memory structures through carefully crafted input data.
The technical implementation of this vulnerability stems from insufficient bounds checking during dynamic buffer allocation and resizing operations within the audio resampling pipeline. When the ff_audio_resample function processes audio data, it attempts to resize internal buffers to accommodate varying audio sample rates and formats. However, the code fails to validate the size parameters or properly handle edge cases during these resizing operations, leading to memory corruption that manifests as a heap overflow. This type of vulnerability maps directly to CWE-122, which specifically addresses heap-based buffer overflow conditions where insufficient memory bounds checking allows attackers to overwrite adjacent heap memory regions.
From an operational perspective, this vulnerability presents significant risks to systems utilizing libav for multimedia processing, particularly those exposed to untrusted input streams. Remote attackers can exploit this flaw by crafting malicious audio files or streams that trigger the vulnerable code path during playback or processing. The impact is primarily a denial of service condition where the application crashes due to memory corruption, potentially leading to service disruption for legitimate users. However, the vulnerability does not appear to enable arbitrary code execution, though it can be leveraged as a vector for more sophisticated attacks in combination with other exploits.
The attack surface for this vulnerability extends across various applications and systems that depend on libav for audio processing capabilities, including media servers, streaming platforms, and multimedia applications. Attackers can leverage this flaw through network-based delivery methods, making it particularly dangerous in environments where users process untrusted media content. The vulnerability aligns with ATT&CK technique T1203, which covers exploitation of software vulnerabilities for denial of service, and demonstrates how seemingly benign multimedia processing functions can become attack vectors when proper input validation is absent.
Mitigation strategies for CVE-2016-6832 primarily involve upgrading to libav version 11.4 or later, which includes patches addressing the buffer overflow conditions in the resample.c file. System administrators should implement comprehensive patch management procedures to ensure all affected systems receive updates promptly. Additionally, deploying input validation mechanisms and restricting access to multimedia processing functions can reduce the attack surface. Network segmentation and monitoring for suspicious audio file processing activities can help detect exploitation attempts. Organizations should also consider implementing sandboxing techniques for multimedia processing components to limit the potential impact of successful exploitation attempts, aligning with defense-in-depth strategies recommended by cybersecurity frameworks.