CVE-2023-45660 : What You Need to Know

A vulnerability has been discovered in Nextcloud Mail, affecting versions prior to 2.2.8 and 3.3.0. The issue, assigned the CVE ID CVE-2023-45660, is classified as a Server-Side Request Forgery (SSRF) vulnerability. Attackers could exploit this flaw to trigger denial of service attacks on third-party servers by abusing the proxy endpoint. It is crucial for Nextcloud Mail users to update to the patched versions to mitigate the risk.

Understanding CVE-2023-45660

Nextcloud Mail, a popular email app for the Nextcloud home server platform, contained a security vulnerability that could be abused by threat actors to disrupt the services of other servers.

What is CVE-2023-45660?

The vulnerability in Nextcloud Mail allows an attacker to conduct Server-Side Request Forgery (SSRF) attacks by bypassing necessary checks, ultimately leading to denial of service attacks on external servers.

The Impact of CVE-2023-45660

If exploited, CVE-2023-45660 could result in significant disruptions to the availability of services on third-party servers, potentially causing financial losses and reputational damage to organizations.

Technical Details of CVE-2023-45660

The vulnerability in Nextcloud Mail is caused by a lack of verification on origin, target, and cookies, enabling attackers to abuse the proxy endpoint for malicious activities.

Vulnerability Description

The SSRF vulnerability in Nextcloud Mail allows threat actors to exploit the proxy endpoint, targeting third-party servers and initiating denial of service attacks.

Affected Systems and Versions

Nextcloud security-advisories < 2.2.8
Nextcloud security-advisories < 3.3.0

Exploitation Mechanism

By exploiting the missing origin, target, and cookies verification, attackers can abuse the proxy endpoint, directing malicious traffic towards external servers.

Mitigation and Prevention

It is imperative for Nextcloud Mail users to take immediate action to protect their systems from potential attacks. Updating to the latest patched versions is crucial to prevent exploitation of this vulnerability.

Immediate Steps to Take

Upgrade Nextcloud Mail to version 2.2.8 or 3.3.0

Long-Term Security Practices

Implement strict cookie requirements for image proxy requests to enhance server security and prevent SSRF attacks.

Patching and Updates

Regularly monitor security advisories and apply updates promptly to mitigate the risk of known vulnerabilities.