CVE-2023-45148 : Security Advisory and Response

This CVE-2023-45148 article provides insights into a vulnerability affecting Nextcloud servers when using Memcached, impacting rate limiting functionality.

Understanding CVE-2023-45148

This CVE involves an improper restriction of excessive authentication attempts in Nextcloud due to reliability issues with the rate limiter when Memcached is utilized in the setup.

What is CVE-2023-45148?

Nextcloud, an open-source home cloud server, faces a vulnerability leading to unexpected rate count resets with the use of Memcached as

memcache.distributed

.

The Impact of CVE-2023-45148

The vulnerability allows malicious actors to bypass rate limiting measures, potentially leading to increased risk of unauthorized access and security breaches.

Technical Details of CVE-2023-45148

The following technical details shed light on the specific aspects of this CVE vulnerability:

Vulnerability Description

Users of Nextcloud Server with Memcached as

memcache.distributed

may encounter premature rate count resets, compromising the effectiveness of rate limiting mechanisms.

Affected Systems and Versions

Versions of Nextcloud server from >= 25.0.0 to < 27.1.0 are impacted, with specific versions like 25.0.11, 26.0.6, and 27.1.0 identified as solutions.

Exploitation Mechanism

The exploitation of this vulnerability involves manipulating rate limiting parameters in a way that allows for the circumvention of authentication controls.

Mitigation and Prevention

To address the CVE-2023-45148 vulnerability, users can take the following measures:

Immediate Steps to Take

Upgrade Nextcloud server to versions 25.0.11, 26.0.6, or 27.1.0 to mitigate the vulnerability. Alternatively, change the config setting

memcache.distributed

to

\OC\Memcache\Redis

and switch to using Redis instead of Memcached.

Long-Term Security Practices

Implement regular security updates and patches, conduct security audits, and adhere to best practices for securing cloud-based services.

Patching and Updates

Stay informed about security advisories and promptly apply patches released by Nextcloud to address known vulnerabilities and enhance system security.