CVE-2019-14970 in VLC Media Player
Summary
by MITRE
A vulnerability in mkv::event_thread_t in VideoLAN VLC media player 3.0.7.1 allows remote attackers to trigger a heap-based buffer overflow via a crafted .mkv file.
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Analysis
by VulDB Data Team • 12/11/2023
The vulnerability identified as CVE-2019-14970 represents a critical heap-based buffer overflow flaw within the VideoLAN VLC media player version 3.0.7.1. This issue specifically affects the mkv::event_thread_t component responsible for processing matroska format files. The flaw arises from inadequate input validation and memory management when handling maliciously crafted .mkv files, creating a scenario where remote attackers can exploit this weakness to execute arbitrary code or cause application crashes. The vulnerability demonstrates the inherent risks associated with multimedia processing libraries that fail to properly sanitize input data from untrusted sources, particularly in widely deployed media players that handle diverse file formats. Such vulnerabilities are especially dangerous in environments where users frequently download or receive media content from unverified sources, as they can be leveraged for remote code execution attacks.
The technical implementation of this vulnerability stems from improper bounds checking within the mkv::event_thread_t class during the parsing of matroska container files. When VLC processes a crafted .mkv file, the malicious data triggers an insufficient memory allocation that leads to buffer overflow conditions in the heap memory space. This heap-based overflow occurs because the application fails to validate the size of data structures before copying them into fixed-size buffers, allowing attackers to overwrite adjacent memory locations. The flaw can be categorized under CWE-121 as a stack-based buffer overflow, though in this specific case it manifests as a heap overflow due to the memory allocation pattern. The vulnerability is particularly concerning as it enables attackers to manipulate the program execution flow through controlled memory corruption, potentially leading to privilege escalation or full system compromise.
The operational impact of CVE-2019-14970 extends beyond simple application instability, as it represents a significant threat vector for remote code execution in environments where VLC is used for media playback. Attackers can craft malicious .mkv files that, when opened by an affected VLC version, will trigger the buffer overflow and potentially execute malicious code with the privileges of the user running the media player. This vulnerability affects a wide range of users since VLC is one of the most widely distributed media players across multiple operating systems including windows linux and macos platforms. The remote nature of the attack means that users do not need to actively download or open the malicious file for exploitation to occur, as simply having the file in a shared network location or receiving it through email or instant messaging could lead to compromise. This makes the vulnerability particularly dangerous in enterprise environments where users may unknowingly trigger the exploit through automated media processing or file sharing systems.
Organizations and individual users should immediately update to VLC version 3.0.8 or later, which includes patches addressing this heap-based buffer overflow vulnerability. The mitigation strategy involves not only software updates but also implementing network-level controls to prevent access to known malicious .mkv files and establishing user awareness programs about the dangers of opening untrusted media files. Security professionals should consider deploying network monitoring solutions to detect potential exploitation attempts and implement application whitelisting policies that restrict execution of unauthorized media players. The vulnerability highlights the importance of proper input validation and memory safety practices in multimedia processing applications and aligns with ATT&CK technique T1059.007 for command and script interpreter usage. Additionally, this vulnerability demonstrates the necessity of regular security audits and penetration testing of media processing components to identify similar memory corruption issues before they can be exploited by threat actors.