CVE-2021-21335 : What You Need to Know

A vulnerability in the SPNEGO HTTP Authentication Module for nginx allows bypassing basic Authentication using a malformed username, affecting versions prior to 1.1.1.

Understanding CVE-2021-21335

This CVE pertains to a flaw in the spnego-http-auth-nginx-module that enables the bypassing of basic authentication via a malformed username.

What is CVE-2021-21335?

The vulnerability in the SPNEGO HTTP Authentication Module for nginx (spnego-http-auth-nginx-module) before version 1.1.1 allows attackers to bypass basic Authentication using a specially crafted username.

The Impact of CVE-2021-21335

The impact of this vulnerability is rated as MEDIUM with a CVSS base score of 5.3. It affects the confidentiality of information as attackers can bypass basic authentication measures.

Technical Details of CVE-2021-21335

This section covers the technical details of the CVE, including the description of the vulnerability, affected systems and versions, and the exploitation mechanism.

Vulnerability Description

In versions of spnego-http-auth-nginx-module before 1.1.1, the basic Authentication can be bypassed by using a malformed username, posing a security risk to users who have enabled basic authentication.

Affected Systems and Versions

The vulnerability affects spnego-http-auth-nginx-module versions prior to 1.1.1, exposing users who have basic authentication enabled to the risk of unauthorized access.

Exploitation Mechanism

Attackers can exploit this vulnerability by using a malformed username to bypass the basic authentication mechanism, potentially gaining unauthorized access to protected resources.

Mitigation and Prevention

In this section, we discuss the steps users and administrators can take to mitigate the risk posed by CVE-2021-21335.

Immediate Steps to Take

To address this vulnerability, users should update the spnego-http-auth-nginx-module to version 1.1.1 or newer. As a workaround, disabling basic authentication can also help mitigate the risk.

Long-Term Security Practices

Implementing strong authentication mechanisms and regularly updating software components can help prevent similar authentication bypass vulnerabilities in the future.

Patching and Updates

Users are advised to apply the latest patches and updates provided by the vendor to ensure that the spnego-http-auth-nginx-module is secure against known vulnerabilities.