CVE-2021-32678 : Security Advisory and Response

A detailed overview of CVE-2021-32678, a vulnerability in Nextcloud Server that allows ratelimits to be bypassed in specific versions.

Understanding CVE-2021-32678

This section delves into the critical aspects of the vulnerability and its potential impact.

What is CVE-2021-32678?

CVE-2021-32678 affects Nextcloud Server versions prior to 19.0.13, 20.0.11, and 21.0.3. It allows ratelimits to be bypassed on OCS API responses, compromising user authentication and enabling potential spam attacks.

The Impact of CVE-2021-32678

The vulnerability poses a low severity risk, but depending on installed applications, it could lead to bypassing authentication ratelimits or spamming other Nextcloud users.

Technical Details of CVE-2021-32678

Explore the technical specifics of the CVE-2021-32678 vulnerability.

Vulnerability Description

Ratelimits are not applied to OCS API responses in affected versions, potentially enabling malicious activities that spam users or bypass authentication mechanisms.

Affected Systems and Versions

Nextcloud Server versions < 19.0.13, >= 20.0.0, < 20.0.11, and >= 21.0.0, < 21.0.3 are impacted by this vulnerability.

Exploitation Mechanism

The vulnerability can be exploited through OCS API controllers using the

@BruteForceProtection

annotation, allowing attackers to bypass ratelimits.

Mitigation and Prevention

Discover the steps to mitigate the risks associated with CVE-2021-32678.

Immediate Steps to Take

Upgrade Nextcloud Server to versions 19.0.13, 20.0.11, or 21.0.3 to patch the vulnerability as no workarounds are available.

Long-Term Security Practices

Maintain a proactive security posture by regularly updating Nextcloud Server and staying informed about security advisories.

Patching and Updates

Stay vigilant for security updates and promptly apply patches to protect your Nextcloud Server from potential vulnerabilities.