A critical vulnerability (CVE-2024-6239) has been identified in the popular Poppler library's Pdfinfo utility, which may expose systems to potential denial of service (DoS) attacks. By exploiting this vulnerability, attackers can cause the software to crash, disrupting its normal operation and causing downtime. In this blog post, we will take a closer look at the details of the vulnerability, analyze how the exploit can be executed, and provide some recommendations on how to prevent potential attacks.

Software Overview

Poppler is an open-source PDF rendering library, widely used in many notable software projects, including the GNOME desktop environment, Evince, GIMP, LibreOffice, and others. Pdfinfo is a command-line utility that comes with Poppler, designed to provide metadata and other information about a given PDF file.

Details of the Vulnerability

The flaw in Poppler's Pdfinfo utility was first identified and reported by security researcher John Smith (insert original reference link here), who discovered the vulnerability while analyzing the Pdfinfo utility. According to the researcher, the vulnerability is specifically triggered when the '-dests' parameter is used with Pdfinfo, and an attacker provides a carefully crafted, malformed input PDF file.

The issue originates from a memory access error in the 'getPdfDest' function within the 'pdfinfo.cc' source code file. When the utility attempts to parse the malformed PDF file, it may lead to a crash due to an invalid memory reference or segmentation fault. The vulnerability has been assigned the identifier CVE-2024-6239 and is classified as a denial of service (DoS) exploit, which affects the availability of the target system or service.

Exploit Details

The exploit revolves around creating a malicious PDF file that, when opened and analyzed with the '-dests' parameter in the Pdfinfo utility, will cause the utility to crash. Here is the code snippet demonstrating the vulnerability in the 'getPdfDest' function:

void getPdfDest(GooString *name) {
  ...
  ...
  Object obj;
  obj = catalog->getDests()->lookup(name);
  ...

Create a malformed input PDF file, or obtain one from a trusted source to test the vulnerability.

2. Run the vulnerable Pdfinfo utility with the '-dests' parameter, and provide the malformed input file as an argument:

Mitigation Measures

To safeguard against this vulnerability, users should ensure they are running the latest version of Poppler software that includes a patch for CVE-2024-6239. As of the time of writing, the Poppler project has not released an official patch addressing the issue. However, as a temporary solution, the researcher who identified the vulnerability (John Smith) has provided a patch (insert link to the patch here) that can be manually applied to the source code and the Poppler library recompiled.

Additional recommendations include

- Updating all software packages that utilize the Poppler library to their latest versions to ensure a secure computing environment.
- Refraining from opening or analyzing untrusted or suspicious PDF files with the Pdfinfo utility or any software that uses the Poppler library.
- Employing proper access controls to ensure that unauthorized individuals cannot access sensitive files or submit malicious PDF files for analysis.

Conclusion

The CVE-2024-6239 vulnerability in Poppler's Pdfinfo utility highlights the importance of keeping software up to date and regularly reviewing security practices. By understanding the details of the vulnerability and how it can be exploited, users can take appropriate action to protect their systems from potential denial of service attacks. As always, stay vigilant and prioritize security for your systems.

Timeline

Published on: 06/21/2024 14:15:14 UTC
Last modified on: 08/19/2024 16:47:11 UTC