CVE-2021-29624 : Exploit Details and Defense Strategies

Fastify-csrf, an open-source plugin protecting Fastify servers against CSRF attacks, was found to have a vulnerability in versions prior to 3.1.0. This CVE brings to light a 'double submit' mechanism using cookies, impacting applications on multiple subdomains.

Understanding CVE-2021-29624

This section covers the essential aspects of the vulnerability.

What is CVE-2021-29624?

Fastify-csrf versions before 3.1.0 are susceptible to a 'double submit' mechanism using cookies, requiring additional 'userInfo' for CSRF token generation.

The Impact of CVE-2021-29624

The vulnerability poses a medium threat with a CVSS base score of 6.5. It can lead to high integrity impact on affected systems.

Technical Details of CVE-2021-29624

Here are the specific technical details related to this CVE.

Vulnerability Description

The issue stems from the reliance on cookies without proper validation and integrity checking, leaving servers open to CSRF attacks.

Affected Systems and Versions

Fastify-csrf versions prior to 3.1.0 are impacted by this vulnerability.

Exploitation Mechanism

Attackers can exploit this vulnerability via a 'double submit' mechanism using cookies, affecting applications on multiple subdomains.

Mitigation and Prevention

Discover the necessary steps to address and prevent the CVE from being exploited.

Immediate Steps to Take

Users are advised to upgrade to version 3.1.0 of fastify-csrf and provide 'userInfo' when generating CSRF tokens for enhanced protection.

Long-Term Security Practices

Implement regular security audits and ensure proper validation and integrity checks on cookies to prevent similar attacks.

Patching and Updates

Stay informed about security advisories, apply patches promptly, and follow secure coding practices to mitigate CSRF risks.