CVE-2017-12779 in mkvalidator
Summary
by MITRE
The Node_GetData function in corec/corec/node/node.c in mkvalidator 0.5.1 allows remote attackers to cause a denial of service (Null pointer dereference and application crash) via a crafted mkv file.
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Analysis
by VulDB Data Team • 01/10/2023
The vulnerability identified as CVE-2017-12779 resides within the mkvalidator 0.5.1 software suite, specifically in the Node_GetData function located in corec/corec/node/node.c. This flaw represents a critical null pointer dereference condition that can be exploited by remote attackers through the careful crafting of malicious mkv video files. The mkvalidator tool is designed for validating matroska files, which are multimedia container formats that can contain various types of media data including video, audio, subtitles, and metadata. The vulnerability manifests when the application processes malformed input files that trigger unexpected behavior in the node data handling mechanism.
The technical exploitation of this vulnerability occurs when an attacker constructs a specially crafted mkv file that contains malformed or unexpected data structures within the file's node hierarchy. When the Node_GetData function attempts to process this malicious input, it fails to properly validate the data pointers before dereferencing them, leading to a null pointer dereference condition. This type of flaw falls under CWE-476 which specifically addresses null pointer dereference vulnerabilities, where a program attempts to access memory through a null pointer, causing an application crash or system instability. The vulnerability represents a classic denial of service scenario where legitimate users cannot access the service due to the application's inability to handle the crafted input properly.
From an operational impact perspective, this vulnerability creates significant security risks for systems that rely on mkvalidator for media file validation or processing. Remote attackers can leverage this flaw to disrupt services by simply sending a malicious mkv file to any system running the vulnerable software. The resulting application crash can lead to complete service unavailability, potentially affecting content delivery systems, media processing pipelines, or validation services that depend on mkvalidator. The attack vector is particularly concerning because it requires no authentication and can be executed remotely, making it accessible to any attacker with network access to the target system.
The mitigation strategies for CVE-2017-12779 should focus on both immediate remediation and long-term defensive measures. The most effective immediate solution involves upgrading to a patched version of mkvalidator where the Node_GetData function has been properly hardened to validate all input pointers before dereferencing them. Security practitioners should also implement input validation controls at network boundaries, filtering out potentially malicious mkv files before they reach the validation system. Additionally, the vulnerability aligns with ATT&CK technique T1499.004 which involves network denial of service attacks, and organizations should consider implementing application whitelisting and sandboxing mechanisms to limit the impact of such vulnerabilities. System administrators should also monitor for unusual patterns of service disruption that could indicate exploitation attempts and implement proper logging to track such incidents for forensic analysis.