CVE-2023-35928 : Security Advisory and Response
Nextcloud Server and Nextcloud Enterprise Server are affected by CVE-2023-35928, allowing users to obtain credentials of other users. Learn the impact and necessary mitigation steps.
A user could use Nextcloud user-scoped external storage to gather credentials of other users, posing a significant security risk.
Understanding CVE-2023-35928
In this section, we will explore the details and impacts of CVE-2023-35928.
What is CVE-2023-35928?
Nextcloud Server versions 25.0.0 to 25.0.7 and 26.0.0 to 26.0.2, along with Nextcloud Enterprise Server versions 19.0.0 to 19.0.13.9, 20.0.0 to 20.0.14.14, 21.0.0 to 21.0.9.12, 22.0.0 to 22.2.10.12, 23.0.0 to 23.0.12.7, 24.0.0 to 24.0.12.2, 25.0.0 to 25.0.7, and 26.0.0 to 26.0.2 could allow a user to access login credentials of another user, compromising their account.
The Impact of CVE-2023-35928
This vulnerability has a high severity base score of 8.5 out of 10, affecting confidentiality, integrity, and availability. An attacker with high privileges can exploit this issue using network access and required user interaction.
Technical Details of CVE-2023-35928
Let's delve deeper into the technical aspects of CVE-2023-35928.
Vulnerability Description
The improper handling of insufficient privileges in Nextcloud's user-scoped external storage feature enables unauthorized users to access sensitive credentials.
Affected Systems and Versions
Nextcloud Enterprise Server and Nextcloud Server versions specified earlier are affected by this vulnerability.
Exploitation Mechanism
Attackers can exploit this vulnerability over the network with low complexity, leading to high impacts on confidentiality, integrity, and availability.
Mitigation and Prevention
Discover the steps to mitigate and prevent CVE-2023-35928.
Immediate Steps to Take
Three effective workarounds include disabling the app files_external, changing the configuration setting to disallow user mount of external storage, and restricting users from creating external storage types like FTP, Nextcloud, SFTP, and WebDAV.
Long-Term Security Practices
In the long term, ensure timely patching and updates for Nextcloud Server and Nextcloud Enterprise Server to prevent exploitation of this vulnerability.