CVE-2019-9717 : Vulnerability Insights and Analysis

A potential denial of service vulnerability exists in the subtitle decoder of Libav 12.3, allowing attackers to cause excessive CPU usage by using a maliciously crafted video file in Matroska format.

Understanding CVE-2019-9717

This CVE involves a vulnerability in Libav 12.3 that can be exploited to perform denial of service attacks.

What is CVE-2019-9717?

The vulnerability in the subtitle decoder of Libav 12.3 enables attackers to manipulate a video file in Matroska format to hog CPU resources.

The Impact of CVE-2019-9717

Exploiting this vulnerability can lead to a denial of service condition by causing high CPU consumption through a specially crafted video file.

Technical Details of CVE-2019-9717

This section provides technical insights into the vulnerability.

Vulnerability Description

The vulnerability is present in the srt_to_ass function within libavcodec/srtdec.c due to a complex format argument in the sscanf function.

Affected Systems and Versions

Affected Version: Libav 12.3
Systems using Libav 12.3 with the vulnerable subtitle decoder

Exploitation Mechanism

Attackers can exploit the vulnerability by utilizing a maliciously crafted video file in Matroska format to trigger excessive CPU usage.

Mitigation and Prevention

Protective measures to address CVE-2019-9717.

Immediate Steps to Take

Update Libav to a patched version that addresses the vulnerability
Avoid opening video files from untrusted or unknown sources

Long-Term Security Practices

Regularly update software and libraries to mitigate known vulnerabilities
Implement network and system monitoring to detect unusual CPU consumption

Patching and Updates

Apply patches provided by Libav to fix the vulnerability
Stay informed about security updates and apply them promptly