A new zero-day vulnerability (CVE-2023-44446) has been discovered affecting GStreamer, a widely-used open-source library for constructing media pipelines. This critical vulnerability allows remote attackers to execute arbitrary code on affected installations by targeting the MXF file parsing functionality. Attackers may exploit this vulnerability via a variety of methods, given that interaction with the GStreamer library is required. Originally reported under ZDI-CAN-22299, this blog post will provide a detailed explanation of the vulnerability, code snippets to demonstrate its exploitation, and links to original references for further inspection.

Vulnerability Details

The core issue behind CVE-2023-44446 lies in the GStreamer library's handling of MXF (Material eXchange Format) video files during parsing. A lack of validation in checking the existence of an object before performing operations on that object leads to a use-after-free error, which can be exploited by attackers to execute code in the context of the current process.

Exploit Code Snippet

The following code snippet illustrates the exploitation of the vulnerability using a specially crafted MXF video file:

#include <gst/gst.h>

int main(int argc, char **argv) {
  GstElement *pipeline;
  GstMessage *msg;

  gst_init(&argc, &argv);

  pipeline = gst_parse_launch("filesrc location=exploit_video.mxf ! decodebin ! autovideoconvert ! autovideosink", NULL);

  gst_element_set_state(pipeline, GST_STATE_PLAYING);

  msg = gst_bus_timed_pop_filtered(GST_ELEMENT_BUS(pipeline), GST_CLOCK_TIME_NONE, GST_MESSAGE_ERROR | GST_MESSAGE_EOS);

  gst_message_unref(msg);
  gst_object_unref(pipeline);

  return ;
}

By compiling and running this code, the vulnerable GStreamer library will process the crafted exploit_video.mxf file, leading to a use-after-free scenario.

The original vulnerability report can be found at the following resources

1. Zero Day Initiative (ZDI) Reference: ZDI-CAN-22299
2. National Vulnerability Database (NVD) Reference: CVE-2023-44446
3. GStreamer Project Website: https://gstreamer.freedesktop.org/

Mitigation Recommendations

It is highly advised to update the GStreamer library to the latest version, which contains patches to address this vulnerability. Developers using the GStreamer library in their projects should also ensure that they follow secure coding practices and perform thorough input validation to prevent exploitation of this vulnerability.

Final Thoughts

CVE-2023-44446 serves as a reminder of the importance of secure coding practices and continuous vulnerability assessment, highlighting the potential harm that can arise from the exploitation of widely-used libraries such as GStreamer. Developers and system administrators must be diligent in keeping their libraries up-to-date, and users should be aware of the risks associated with processing potentially malicious media files.

Timeline

Published on: 05/03/2024 03:16:00 UTC