Cybersecurity researchers have recently discovered a critical vulnerability, identified as CVE-2024-47177, in the widely used open-source printing system, CUPS (Common Unix Printing System), and the cups-filters software package. This vulnerability enables an attacker to execute arbitrary commands on affected systems, potentially compromising these devices and allowing unauthorized access to sensitive information.
Exploit Details
The main issue lies in the FoomaticRIPCommandLine function, which is part of the CUPS filters package (used for processing print jobs). The function passes any value given to it through a PPD (PostScript Printer Description) file. The exploit takes advantage of this behavior by supplying a crafted PPD file containing a malicious command. The unauthorized command is executed when processing print jobs.
An attacker could leverage this vulnerability to gain unauthorized access to a victim's system. The remote command execution could potentially allow an attacker to gain control of the affected device, manipulate data, or cause printers to malfunction.
This vulnerability is particularly dangerous when combined with another recently discovered logic bug, CVE-2024-47176. This second vulnerability significantly increases the potential impact, enabling attackers to execute these malicious commands remotely.
The following is a simple example of a malformed PPD file containing a malicious command
*FoomaticRIPCommandLine: "sh -c 'echo HACKED > /tmp/hacked.txt' %A %B %C"
When processed by the targeted CUPS filters system, the command-line within the PPD file will execute sh -c 'echo HACKED > /tmp/hacked.txt', which will create a new file called "hacked.txt" with the text "HACKED" inside.
For more information about this vulnerability, please refer to the official security advisories
1. CUPS Security Advisory (CVE-2024-47177)
2. Cups-Filters security page (CVE-2024-47177)
Mitigation
At the time of writing this post, the developers of CUPS and Cups-Filters have addressed the vulnerability. It is highly recommended to update your affected systems to the latest version available which contains the necessary security patches.
For cups-filters, upgrade to version 1.30.1 or later.
In addition to applying the patches, users should be cautious when receiving and processing print jobs from untrusted sources. Avoid opening or processing suspicious PPD files, and ensure that access to printing services is limited to authorized users only.
Conclusion
The CVE-2024-47177 vulnerability poses a considerable risk to affected systems due to the potential for remote command execution via a crafted PPD file. Keeping software up to date and following proper security practices are essential to mitigating the risk of exploitation.
Timeline
Published on: 09/26/2024 22:15:04 UTC
Last modified on: 09/30/2024 12:46:20 UTC