CVE-2023-25820 : What You Need to Know

This CVE impacts Nextcloud Server and Nextcloud Enterprise Server versions prior to specified releases, leading to a vulnerability in the password confirmation modal.

Understanding CVE-2023-25820

This vulnerability involves the lack of brute force protection on the password confirmation modal in Nextcloud Server and Nextcloud Enterprise Server, allowing attackers to potentially brute force passwords on the confirmation endpoint.

What is CVE-2023-25820?

The vulnerability in Nextcloud Server and Nextcloud Enterprise Server versions prior to the designated updates enables attackers to perform brute force attacks on user passwords after gaining access to an authenticated user session.

The Impact of CVE-2023-25820

With a CVSS base score of 4.2 (Medium severity), this vulnerability poses a risk to the confidentiality, integrity, and availability of affected systems. Attackers with local access and low privileges can exploit this issue, requiring user interaction to carry out the attack.

Technical Details of CVE-2023-25820

This vulnerability, categorized under CWE-307 (Improper Restriction of Excessive Authentication Attempts), affects various versions of Nextcloud Server and Nextcloud Enterprise Server.

Vulnerability Description

The vulnerability allows unauthorized individuals to conduct brute force password attacks on the password confirmation endpoint of affected Nextcloud Server and Nextcloud Enterprise Server versions.

Affected Systems and Versions

Nextcloud Server versions 24.0.x before 24.0.10 and 25.0.x before 25.0.5, as well as Nextcloud Enterprise Server versions 21.x to 25.x before specific releases, are impacted by this vulnerability.

Exploitation Mechanism

Attackers exploit this vulnerability by compromising an authenticated user session and then attempting brute force attacks on the password confirmation modal, potentially compromising user credentials.

Mitigation and Prevention

To address CVE-2023-25820, immediate actions and long-term security practices are recommended to mitigate the risk associated with this vulnerability.

Immediate Steps to Take

Affected users are advised to update Nextcloud Server to at least version 24.0.10 or 25.0.5 and Nextcloud Enterprise Server to the recommended patched versions to address this vulnerability.

Long-Term Security Practices

Implementing strong password policies, enabling multi-factor authentication, and regularly updating software are essential practices to enhance the overall security posture of Nextcloud deployments.

Patching and Updates

Users should promptly apply the provided patches for Nextcloud Server and Nextcloud Enterprise Server versions to prevent exploitation of this vulnerability. No known workarounds are available, making patching the most effective response to this issue.