CVE-2020-8118 : Security Advisory and Response

An authenticated server-side request forgery vulnerability in Nextcloud Server 16.0.1 allowed attackers to detect local and remote services when adding a new subscription in the calendar application.

Understanding CVE-2020-8118

This CVE involves a Server-Side Request Forgery (SSRF) vulnerability in Nextcloud Server 16.0.1.

What is CVE-2020-8118?

CVE-2020-8118 is an authenticated SSRF vulnerability in Nextcloud Server 16.0.1 that enables the detection of local and remote services during the addition of a new subscription in the calendar application.

The Impact of CVE-2020-8118

The vulnerability could be exploited by authenticated attackers to gather information about internal and external services, potentially leading to further attacks or unauthorized access.

Technical Details of CVE-2020-8118

This section provides more in-depth technical insights into the vulnerability.

Vulnerability Description

The SSRF vulnerability in Nextcloud Server 16.0.1 allows authenticated users to probe and identify local and remote services when creating a new calendar subscription.

Affected Systems and Versions

Product: Nextcloud Server
Version: 16.0.1

Exploitation Mechanism

Attackers with authenticated access can exploit this vulnerability by manipulating the server to make requests to arbitrary destinations, enabling them to gather information about services.

Mitigation and Prevention

Protecting systems from CVE-2020-8118 requires immediate actions and long-term security practices.

Immediate Steps to Take

Apply security patches provided by Nextcloud promptly.
Monitor and restrict network requests made by the calendar application.
Educate users on the risks of SSRF attacks and the importance of secure coding practices.

Long-Term Security Practices

Implement strict input validation to prevent SSRF vulnerabilities.
Regularly update and patch software to address security flaws.
Conduct security audits and penetration testing to identify and mitigate vulnerabilities.
Stay informed about security advisories and best practices in secure application development.

Patching and Updates

Nextcloud has released security updates to address CVE-2020-8118. Ensure that you apply the latest patches to mitigate the SSRF vulnerability.