CVE-2023-5978 : Security Advisory and Response

This CVE-2023-5978 was published by FreeBSD on November 8, 2023. The vulnerability is related to the incorrect manipulation of libcap_net limitation lists in certain versions of FreeBSD 13-RELEASE before 13-RELEASE-p5.

Understanding CVE-2023-5978

This section will provide an in-depth understanding of the CVE-2023-5978 vulnerability in FreeBSD.

What is CVE-2023-5978?

In versions of FreeBSD 13-RELEASE prior to 13-RELEASE-p5, a vulnerability exists in the cap_net libcasper(3) service. Under specific circumstances, the service incorrectly validates updated constraints as strictly subsets of active constraints. This could lead to a scenario where an application, when specifying only a list of resolvable domain names without any other limitations, could submit a new list of domains that include entries not previously listed. This oversight could potentially allow the application to resolve domain names that were previously restricted.

The Impact of CVE-2023-5978

The impact of this vulnerability is classified under CWE-269 (Improper Privilege Management). Exploitation of this vulnerability could lead to unauthorized resolution of domain names, bypassing intended restrictions, and potentially allowing malicious actors to access resources that should have been restricted.

Technical Details of CVE-2023-5978

In this section, we will delve into the technical aspects of the CVE-2023-5978 vulnerability in FreeBSD.

Vulnerability Description

The vulnerability arises from the incorrect validation of updated constraints in the cap_net libcasper(3) service. This allows for the introduction of new domain names that were not previously listed, potentially leading to unauthorized resolution.

Affected Systems and Versions

The vulnerability affects versions of FreeBSD 13-RELEASE before 13-RELEASE-p5 that utilize the cap_net libcasper(3) service.

Exploitation Mechanism

Exploitation of this vulnerability involves submitting a new list of domains, including entries not initially listed, when only a list of resolvable domain names has been specified without additional limitations.

Mitigation and Prevention

To mitigate the risks associated with CVE-2023-5978, it is crucial to take immediate steps and implement long-term security practices.

Immediate Steps to Take

Update FreeBSD systems running affected versions to at least 13-RELEASE-p5 to address this vulnerability.
Monitor network traffic and domain resolution activities for any suspicious behavior.

Long-Term Security Practices

Regularly update and patch FreeBSD systems to ensure the latest security fixes are in place.
Implement network segmentation and access controls to limit the impact of potential exploitation.

Patching and Updates

Ensure timely application of security updates provided by FreeBSD to address CVE-2023-5978 and other known vulnerabilities. Regularly check for advisories from FreeBSD to stay informed about security patches and best practices.