CVE-2023-6604: FFmpeg Vulnerability - Demuxing Arbitrary Data as XBIN Format and Degraded Performance

A new security vulnerability has been discovered in FFmpeg, which is assigned the CVE-ID CVE-2023-6604. This flaw allows an attacker to cause unexpected additional CPU load and storage consumption, which can lead to degraded performance or potential denial of service (DoS). The vulnerability is triggered when demuxing arbitrary data without proper validation as XBIN-formatted data. In this article, we will delve into the origin of this vulnerability, explore its potential impact, and discuss possible mitigation strategies.

Code Snippet

The vulnerable code implementation in FFmpeg's implementation of the XBIN demux function. Below is the code snippet from FFmpeg where the issue resides:

static int xbin_read_header(AVFormatContext *s)
{
    AVCodecParameters *video_par = av_add_codec_para(s, AVMEDIA_TYPE_VIDEO, AV_CODEC_ID_XBIN);
    
    int ret = avio_read(s->pb, video_par->extradata,2);

    video_par->data_with = avio_rb16(s->pb);
    video_par->height = avio_rb24(s->pb);
    ...
}

In this code, if the input data is not proper XBIN format data, the failure to validate and process this incorrect data can lead to excessive CPU load and storage consumption, causing a degraded performance or denial of service attack.

Original References

- FFmpeg's GitHub Repository: https://github.com/FFmpeg/FFmpeg
- FFmpeg's Security Advisory: https://ffmpeg.org/security.html
- CVE Details in NIST NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-6604

Exploit Details

An attacker can exploit this vulnerability by sending arbitrary non-XBIN format data to be demuxed as XBIN data by FFmpeg. The absence of proper input format validation causes an acceleration in CPU and storage use, leading to performance degradation or DoS. An example exploit scenario could consist of an attacker creating a malicious video file crafted to exploit this vulnerability and distributing it. Once a user attempts to play this video with a media player that utilizes FFmpeg for processing, the vulnerability could be triggered.

Mitigation Strategies

To mitigate the impact of this vulnerability, it's highly recommended to apply any security patches provided by FFmpeg as soon as they become available. Additionally, one can inspect their logs for any unusual CPU and storage consumption patterns indicating an exploitation attempt of this vulnerability.

Conclusion

There you have it - a comprehensive look into CVE-2023-6604, a significant vulnerability in FFmpeg that can lead to degraded performance or denial of service attacks. In this article, we've covered the origin of the vulnerability, provided a code snippet of the problematic implementation, original references of the concerning issue, detailed the exploit method, and discussed possible mitigation strategies. It's crucial to be aware of security vulnerabilities such as this, particularly when they affect widely-used libraries such as FFmpeg, to ensure the security of various applications and users alike.

Timeline

Published on: 01/06/2025 17:15:14 UTC