CVE-2021-32705 : What You Need to Know

A lack of ratelimit on the public DAV endpoint in Nextcloud Server versions prior to 19.0.13, 20.0.11, and 21.0.3 could allow attackers to enumerate valid share tokens or credentials.

Understanding CVE-2021-20657

CVE-2021-32705 is a vulnerability in Nextcloud Server that could potentially lead to unauthorized access to sensitive data.

What is CVE-2021-20657?

Nextcloud Server versions below 19.0.13, 20.0.11, and 21.0.3 lacked ratelimiting on the public DAV endpoint, opening up the possibility for attackers to guess valid share tokens or credentials.

The Impact of CVE-2021-20657

The impact of this vulnerability is rated as MEDIUM with a CVSS base score of 5.3. It has a low attack complexity and requires no special privileges for exploitation. The lack of ratelimiting could compromise data integrity.

Technical Details of CVE-2021-20657

This section provides a detailed overview of the vulnerability.

Vulnerability Description

The lack of ratelimiting on the public DAV endpoint in affected Nextcloud Server versions could facilitate unauthorized credential enumeration by malicious actors.

Affected Systems and Versions

Nextcloud Server versions prior to 19.0.13, 20.0.11, and 21.0.3 are impacted by this vulnerability.

Exploitation Mechanism

Attackers can exploit this vulnerability over the network with low attack complexity, potentially compromising data integrity.

Mitigation and Prevention

To address CVE-2021-32705, follow these recommendations:

Immediate Steps to Take

Update Nextcloud Server to versions 19.0.13, 20.0.11, or 21.0.3 to patch the vulnerability and prevent unauthorized access.

Long-Term Security Practices

Maintain regular security updates for Nextcloud Server and implement strong access controls and monitoring to mitigate future risks.

Patching and Updates

Regularly check for security advisories and patches from Nextcloud to stay protected against known vulnerabilities.