CVE-2017-17670 in VLC Media Player
Summary
by MITRE
In VideoLAN VLC media player through 2.2.8, there is a type conversion vulnerability in modules/demux/mp4/libmp4.c in the MP4 demux module leading to a invalid free, because the type of a box may be changed between a read operation and a free operation.
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Analysis
by VulDB Data Team • 01/27/2021
The vulnerability identified as CVE-2017-17670 represents a critical type conversion flaw within the VideoLAN VLC media player version 2.2.8 and earlier. This issue resides in the MP4 demux module specifically within the modules/demux/mp4/libmp4.c file, where improper handling of box type conversions creates a dangerous condition that can lead to memory corruption. The flaw manifests when the application processes MP4 media files and encounters specific malformed or crafted content that triggers unexpected behavior in the demultiplexing process.
The technical nature of this vulnerability stems from a race condition or state inconsistency where the type of a box structure can change between the time it is read and when it is subsequently freed. This type conversion inconsistency creates a scenario where the application may attempt to free memory using an incorrect type identifier, resulting in an invalid free operation. Such conditions are particularly dangerous because they can lead to memory corruption, arbitrary code execution, or application crashes. The vulnerability specifically targets the MP4 demux module's handling of media file structures, where box elements contain metadata and data about the media content, and improper type management during processing can cause severe operational consequences.
From an operational perspective, this vulnerability poses significant risks to users who process multimedia content through VLC media player, particularly in environments where untrusted or malicious media files might be encountered. The impact extends beyond simple application instability to potential security exploitation, as the invalid free operation can be leveraged to execute arbitrary code or cause denial of service conditions. Attackers could craft specially formatted MP4 files that trigger this vulnerability when opened by VLC, potentially leading to complete system compromise. The vulnerability affects a widely used media player across multiple platforms, amplifying its potential impact across diverse user bases and environments.
The vulnerability aligns with CWE-459, which describes "Incomplete Cleanup" and specifically addresses issues related to improper resource management, particularly in scenarios where object lifecycles are not properly tracked or managed. Additionally, this weakness can be categorized under ATT&CK technique T1059, where adversaries may leverage application vulnerabilities to execute malicious code through media processing applications. The flaw demonstrates poor input validation and memory management practices that are common in multimedia processing applications where complex file format parsing occurs. Organizations using VLC for media playback should prioritize immediate patching to address this vulnerability, as it represents a significant risk to system security and stability.
Mitigation strategies should focus on immediate patch deployment for VLC media player versions prior to 3.0.0, as this vulnerability was addressed in subsequent releases. System administrators should also implement additional security controls such as restricting media file processing to trusted sources, employing sandboxing techniques for media file handling, and monitoring for unusual application behavior that might indicate exploitation attempts. Network-level controls can help by filtering media file types or implementing deep packet inspection for suspicious content patterns. Regular security updates and vulnerability assessments should be conducted to ensure that multimedia applications remain protected against similar memory management flaws, as these types of vulnerabilities continue to represent significant attack vectors in modern computing environments.