A new security vulnerability, CVE-2023-39005, has been discovered which affects OPNsense, a widely-used open-source firewall and routing software platform. Specifically, this vulnerability relates to insecure permissions found within configd.socket in versions of OPNsense before 23.7. In this post, we will analyze this vulnerability, review code snippets showcasing the issue, provide links to original references, and discuss potential exploit details.


OPNsense (https://opnsense.org) is an open-source and easy-to-use firewall and routing platform that comes with a suite of powerful features. It is built on the solid foundation of FreeBSD, which is well-known for its security, stability, and performance. The project aims to provide a flexible, powerful, yet user-friendly solution for network security.

The Vulnerability: Insecure Permissions in configd.socket (CVE-2023-39005)

This vulnerability is caused by insecure permissions in the configd.socket file, which can be found in OPNsense installations before version 23.7. Essentially, the problematic permissions can allow unauthorized users to gain access to system settings and interrupt essential network services. In some cases, this can lead to loss of network connectivity and potential security risks.

The following code snippet depicts the insecure permissions found in the configd.socket file


The insecure permission can be seen with the SocketMode=0666 line, which means that any user on the system can read, write, and execute the socket. This permission configuration can result in unauthorized access to sensitive system settings and services.

1. The official OPNsense GitHub repository: https://github.com/opnsense
2. The related CVE entry on Mitre CVE database: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-39005

Exploit Details

An attacker with local access to the affected OPNsense system could potentially exploit this vulnerability by connecting to the insecurely configured configd.socket and sending arbitrary control commands to manipulate system settings. This can lead to unintended consequences and potentially allow an attacker to interrupt crucial network services, monitor network traffic, or even compromise the entire OPNsense system.

To exploit this vulnerability, an attacker would need to have local access to the affected system, knowledge of the configd.socket location, and an understanding of how to use it to submit malicious control commands.


To mitigate this vulnerability, administrators of affected OPNsense installations should promptly upgrade their systems to version 23.7 or later, as this version includes a fix for the insecure permissions in configd.socket. Upgrading to the latest version will ensure that OPNsense installations are protected against this potential threat and other newly discovered vulnerabilities.

In conclusion, CVE-2023-39005 represents a potentially dangerous vulnerability in OPNsense systems stemming from insecure permissions in configd.socket. By understanding the vulnerability, reviewing the code snippets, discovering original references, and recognizing potential exploit details, administrators can take actionable steps to protect their systems and networks. Be sure to stay informed about new vulnerabilities by tracking updates and upgrading when necessary.


Published on: 08/09/2023 19:15:00 UTC
Last modified on: 08/15/2023 17:52:00 UTC