CVE-2016-7393 in libav
Summary
by MITRE
Stack-based buffer overflow in the aac_sync function in aac_parser.c in Libav before 11.5 allows remote attackers to cause a denial of service (out-of-bounds read) via a crafted file.
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Analysis
by VulDB Data Team • 08/15/2020
The vulnerability identified as CVE-2016-7393 represents a critical stack-based buffer overflow within the Libav multimedia framework, specifically affecting the aac_sync function in the aac_parser.c source file. This flaw exists in Libav versions prior to 11.5 and exposes systems to remote exploitation through crafted malicious files that trigger out-of-bounds read conditions. The vulnerability stems from inadequate input validation and boundary checking within the audio parsing logic that processes Advanced Audio Coding format files, making it particularly dangerous in environments where multimedia file processing is automated or untrusted content is handled.
The technical implementation of this vulnerability occurs when the aac_sync function attempts to parse AAC audio data without sufficient validation of buffer boundaries during the synchronization process. When a maliciously crafted AAC file is processed, the function fails to properly check array indices or buffer limits, allowing an attacker to manipulate memory access patterns that result in reading data beyond the allocated buffer space. This behavior manifests as an out-of-bounds read condition that can cause application crashes or unpredictable behavior, ultimately leading to denial of service scenarios. The stack-based nature of the overflow indicates that the vulnerability affects local variables allocated on the program's call stack, making it particularly susceptible to exploitation through carefully constructed input sequences.
From an operational perspective, this vulnerability poses significant risks to multimedia processing systems, streaming services, and content management platforms that rely on Libav for audio file handling. The remote attack vector means that adversaries can exploit this flaw from outside the target environment, making it particularly dangerous for web applications, media servers, and content delivery networks that process user-uploaded audio files. The denial of service impact can result in complete service disruption, potentially affecting thousands of users depending on the scale of the affected system. Security researchers have classified this vulnerability according to CWE-121, which specifically addresses stack-based buffer overflow conditions, and it aligns with ATT&CK technique T1203, which covers legitimate program execution through process injection and system manipulation.
Organizations affected by this vulnerability should prioritize immediate patching of all Libav installations to version 11.5 or later, where the buffer overflow has been addressed through improved input validation and boundary checking mechanisms. Additional mitigations include implementing strict file format validation, deploying sandboxing techniques for multimedia processing, and establishing network segmentation to limit the potential impact of successful exploitation attempts. Security monitoring should focus on detecting unusual patterns in file processing activities and implementing automated scanning for malicious media files. The vulnerability demonstrates the importance of thorough input validation in multimedia processing libraries and highlights the need for continuous security auditing of widely-used open source components that handle untrusted data input.