CVE-2023-28645 : What You Need to Know

This CVE involves the bypassing of the secure view feature in Nextcloud richdocuments by utilizing an unprotected internal API endpoint. It has a CVSS base score of 5.7, with a medium severity level.

Understanding CVE-2023-28645

This CVE pertains to a vulnerability in Nextcloud richdocuments that allows bypassing the secure view feature, potentially leading to improper access control.

What is CVE-2023-28645?

In affected versions, the Nextcloud richdocuments app's secure view feature can be bypassed by exploiting an unprotected internal API endpoint. This vulnerability, known as CWE-284 (Improper Access Control), poses a high risk to the confidentiality of sensitive information.

The Impact of CVE-2023-28645

The vulnerability could allow unauthorized users to access confidential documents without proper authentication, compromising data integrity and confidentiality within the Nextcloud richdocuments environment.

Technical Details of CVE-2023-28645

This section provides more insight into the vulnerability, including its description, affected systems and versions, and exploitation mechanism.

Vulnerability Description

The issue lies in the secure view feature of Nextcloud richdocuments, which can be circumvented by using an unprotected internal API endpoint, potentially leading to unauthorized access to sensitive documents.

Affected Systems and Versions

The vulnerability affects Nextcloud richdocuments versions prior to 8.0.0-beta.1, 7.0.2, and 6.3.2. Specifically, versions >= 7.0.0 and < 7.0.2, as well as versions < 6.3.2 are impacted by this vulnerability.

Exploitation Mechanism

By leveraging the unprotected internal API endpoint in Nextcloud richdocuments, threat actors can sidestep the secure view feature and access documents without proper authorization, posing a significant security risk.

Mitigation and Prevention

To address CVE-2023-28645, immediate steps should be taken to mitigate the vulnerability and prevent potential exploitation.

Immediate Steps to Take

Users are advised to upgrade the Nextcloud Office app (richdocuments) to versions 8.0.0-beta.1, 7.0.2, or 6.3.2 to effectively patch the vulnerability. Alternatively, restricting document download capabilities and configuring the WOPI setting to serve documents only between Nextcloud and Collabora can help mitigate the risk.

Long-Term Security Practices

Implementing robust access controls, regularly updating software and security configurations, and conducting thorough security assessments can enhance the overall security posture of Nextcloud richdocuments and mitigate similar vulnerabilities in the future.

Patching and Updates

It is crucial for organizations using Nextcloud richdocuments to stay informed about security advisories and promptly apply patches and updates provided by the vendor to address known vulnerabilities and enhance the security of their systems.