CVE-2021-31403 : Security Advisory and Response

This article provides detailed information about CVE-2021-31403, a timing side channel vulnerability in the UIDL request handler of Vaadin 7 and 8.

Understanding CVE-2021-31403

This section covers the vulnerability details and its impact.

What is CVE-2021-31403?

CVE-2021-31403 is a non-constant-time comparison vulnerability in the UIDL request handler of com.vaadin:vaadin-server versions 7.0.0 through 7.7.23 and 8.0.0 through 8.12.2. This flaw allows an attacker to guess a security token through a timing attack.

The Impact of CVE-2021-31403

The impact of this vulnerability is rated as medium severity with a CVSS base score of 4.0. It has a high attack complexity, local attack vector, and affects confidentiality and integrity.

Technical Details of CVE-2021-31403

This section dives into the vulnerability description, affected systems, and the exploitation mechanism.

Vulnerability Description

The vulnerability arises from non-constant-time comparison of CSRF tokens in the UIDL request handler of Vaadin versions 7.0.0 through 7.7.23 and 8.0.0 through 8.12.2.

Affected Systems and Versions

The vulnerability impacts Vaadin 7.0.0 through 7.7.23, and Vaadin 8.0.0 through 8.12.2.

Exploitation Mechanism

Attackers can exploit this vulnerability by performing a timing attack to guess the security token.

Mitigation and Prevention

In this section, we discuss the immediate steps to take to secure systems and best practices for long-term security.

Immediate Steps to Take

Users and administrators are advised to apply security patches provided by Vaadin promptly. Additionally, monitoring for any suspicious activities is recommended.

Long-Term Security Practices

Implementing secure coding practices, regular security assessments, and staying informed about security updates are essential for long-term security.

Patching and Updates

Ensure that systems are regularly updated with the latest security patches to mitigate the risk of exploitation.