CVE-2023-39963 : Security Advisory and Response

This article provides insights into CVE-2023-39963, a vulnerability in Nextcloud Server that allows unauthorized creation of app passwords.

Understanding CVE-2023-39963

This CVE highlights a security flaw in Nextcloud Server versions that enables threat actors to generate app passwords without proper authorization.

What is CVE-2023-39963?

Nextcloud Server, utilized for data storage within the Nextcloud cloud platform, is vulnerable to a missing password confirmation flaw. Attackers can exploit this to create app passwords post-session hijacking.

The Impact of CVE-2023-39963

The vulnerability, found in Nextcloud Server versions 20.0.0 to 27.0.1, poses a high risk with a CVSS base score of 8.1. It can lead to unauthorized creation of app passwords, compromising user data confidentiality and integrity.

Technical Details of CVE-2023-39963

This section delves into the specifics of the vulnerability affecting Nextcloud Server.

Vulnerability Description

The missing password confirmation flaw in Nextcloud Server versions permits attackers to create app passwords after seizing a user's session, potentially compromising sensitive data.

Affected Systems and Versions

Nextcloud Server versions impacted include 20.0.0 to 27.0.1. Notably, specific versions, such as 25.0.9, 26.0.4, and 27.0.1, contain patches to address this vulnerability.

Exploitation Mechanism

Threat actors can exploit the missing password confirmation flaw to create unauthorized app passwords upon successful session theft, leading to a security breach.

Mitigation and Prevention

Learn how to mitigate the risks associated with CVE-2023-39963 and prevent unauthorized app password creation.

Immediate Steps to Take

Update Nextcloud Server to patched versions, including 25.0.9, 26.0.4, and 27.0.1, to safeguard against potential exploitation.

Long-Term Security Practices

Adopt robust security practices, such as enforcing multi-factor authentication and regular security audits, to enhance overall system protection.

Patching and Updates

Ensure timely installation of security patches and updates provided by Nextcloud to address known vulnerabilities like the missing password confirmation issue in affected versions.