CVE-2023-4508 – Denial-of-Service Vulnerability in Gerbv (versions 2.4. to 2.10.) – Exploiting Gerber RS-274X File Input Control

Gerbv is a popular open-source Gerber file viewer widely used in the electronics industry to visualize RS-274X standard files generated during the PCB design process. A newly discovered vulnerability with the CVE-ID of CVE-2023-4508 affects Gerbv versions 2.4. to 2.10.. This vulnerability allows threat actors, who have control over a file input to Gerbv, to cause a crash and subsequent denial-of-service (DoS) via a specially crafted Gerber RS-274X file.

This article will delve into the details of the vulnerability, including how to recreate and exploit the vulnerability using a code snippet, and the importance of patching affected versions. We will also provide links to original references for more information.

Code Snippet

To trigger the denial-of-service with CVE-2023-4508, the attacker needs to create a malicious Gerber RS-274X file that includes specific malformed entities causing Gerbv's internal parser to crash.

The following code snippet demonstrates an example of a specially crafted Gerber RS-274X file

%FSLAX23Y23*%
%MOMM*%
%ADD10C,.5*%
%ADD11R,2.54X1.27*%
%AB D10*%
%LPD*%
%IPPOS*%
%AMOC8*
5,1,8,,,2.032,1.908*
%
D10*
X010200Y050D02*
X010200Y060D01*
X010200Y050D02*
M02*

In this example, the "%AMOC8*" block with the malformed parameters is the key element that leads to the crash. The file will cause a buffer overflow when loaded into the vulnerable versions of Gerbv, leading to a denial-of-service.

Original References

[1] CVE-2023-4508: Gerbv Denial of Service Vulnerability.
National Vulnerability Database (NVD) - https://nvd.nist.gov/vuln/detail/CVE-2023-4508

[2] Gerbv Project Homepage. Gerbv – A Free/Open Source Gerber Viewer. - http://gerbv.sourceforge.net/

[3] Gerber Format (RS-274X). Ucamco. https://www.ucamco.com/files/downloads/file/81/the_gerber_file_format_specification.pdf

Exploit Details

This vulnerability can be exploited by an attacker in several ways, but the most common scenarios would include:

1. Social Engineering: Convincing a Gerbv user to open a specially crafted Gerber RS-274X file received through a phishing email or a message.

2. Supply Chain Attacks: Injecting/Modifying Gerber RS-274X files during the PCB design, manufacturing, or supply chain process to cause denial-of-service for users, factory equipment, or any system that processes Gerber files using Gerbv.

Conclusion

A denial-of-service vulnerability (CVE-2023-4508) has been identified in Gerbv versions 2.4. to 2.10. that allows attackers to cause a crash and service disruption by exploiting file input control when visualizing malicious Gerber RS-274X files.

As a Gerbv user or developer, it’s critical to apply the necessary patches and updates to close this vulnerability. Additionally, exercising caution when opening and processing Gerber RS-274X files from untrusted sources or using alternative, unaffected software can reduce the chances of a successful exploit.

For more information on CVE-2023-4508 and updates on how Gerbv is addressing the issue, please visit the official Gerbv project homepage and the National Vulnerability Database (NVD) links provided under "Original References" above.

Timeline

Published on: 08/24/2023 23:15:09 UTC
Last modified on: 09/30/2023 17:15:39 UTC