CVE-2019-14534 in VLC Media Player
Summary
by MITRE
In VideoLAN VLC media player 3.0.7.1, there is a NULL pointer dereference at the function SeekPercent of demux/asf/asf.c that will lead to a denial of service attack.
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Analysis
by VulDB Data Team • 12/07/2023
The vulnerability identified as CVE-2019-14534 represents a critical NULL pointer dereference flaw within the VideoLAN VLC media player version 3.0.7.1. This issue specifically manifests within the demux/asf/asf.c source file at the SeekPercent function, where improper input validation leads to a crash condition that can be exploited by malicious actors. The flaw occurs when the media player processes ASF (Advanced Systems Format) media files, which are commonly used for streaming and broadcasting multimedia content. This vulnerability falls under the CWE-476 category of NULL Pointer Dereference, a well-documented weakness that has been consistently ranked among the top software security risks by various industry organizations including the OWASP Top Ten project. The vulnerability demonstrates a clear operational impact that aligns with the ATT&CK framework's privilege escalation and denial of service tactics, as it allows an attacker to disrupt the normal operation of the affected system.
The technical implementation of this vulnerability stems from insufficient boundary checking and null validation within the SeekPercent function that handles seeking operations within ASF files. When processing malformed or specially crafted ASF media files, the function fails to properly validate pointer references before dereferencing them, leading to an immediate crash of the VLC media player application. This crash occurs because the application attempts to access memory locations that have not been properly initialized or allocated, resulting in a segmentation fault or access violation. The vulnerability is particularly concerning as it can be triggered through simple file manipulation without requiring any special privileges or complex attack vectors, making it highly exploitable in various threat scenarios including social engineering campaigns where users might unknowingly open malicious media files.
The operational impact of CVE-2019-14534 extends beyond simple denial of service, as it can be leveraged to create persistent disruptions in media playback environments, particularly in enterprise settings where VLC is commonly used for video conferencing, training materials, and digital signage applications. Attackers can craft malicious ASF files that will cause the VLC player to crash whenever they are opened or when the player attempts to seek to specific positions within the media file. This behavior creates a reliable method for conducting denial of service attacks against systems running vulnerable versions of VLC, potentially affecting thousands of users if the malicious files are distributed through common channels. The vulnerability's exploitation aligns with ATT&CK technique T1499.004 which focuses on network denial of service attacks, and demonstrates how seemingly benign media playback functionality can become a vector for system disruption.
Mitigation strategies for CVE-2019-14534 should prioritize immediate software updates to version 3.0.8 or later, where the NULL pointer dereference has been addressed through proper input validation and pointer initialization. System administrators should implement comprehensive patch management protocols to ensure all vulnerable instances are updated promptly, as the vulnerability affects a widely used media player that is deployed across numerous operating systems including Windows, macOS, and Linux platforms. Additional defensive measures include implementing file validation policies that scan media files for potential malicious content before processing, utilizing network segmentation to limit exposure, and monitoring for unusual application crash patterns that might indicate exploitation attempts. Organizations should also consider implementing application whitelisting policies that restrict the execution of unauthorized media player versions, while maintaining regular security assessments to identify and remediate similar vulnerabilities in other media processing components. The remediation process should follow established security frameworks such as those recommended by NIST SP 800-40 and ISO 27001 standards for vulnerability management and incident response procedures.