CVE-2021-45115 : What You Need to Know

An issue was discovered in Django 2.2 before 2.2.26, 3.2 before 3.2.11, and 4.0 before 4.0.1, which could lead to a denial-of-service attack.

Understanding CVE-2021-45115

This CVE pertains to a vulnerability in Django versions 2.2, 3.2, and 4.0.

What is CVE-2021-45115?

Django versions 2.2 through 4.0 suffer from a weakness where UserAttributeSimilarityValidator took substantial time to evaluate a large password, potentially providing a DoS attack vector.

The Impact of CVE-2021-45115

Exploiting this vulnerability could result in a denial-of-service attack if an attacker has unrestricted access to user registration.

Technical Details of CVE-2021-45115

This section provides technical details about the vulnerability.

Vulnerability Description

UserAttributeSimilarityValidator in Django incurred significant overhead when validating large passwords, creating a potential for a denial-of-service attack.

Affected Systems and Versions

Django 2.2 before 2.2.26
Django 3.2 before 3.2.11
Django 4.0 before 4.0.1

Exploitation Mechanism

The vulnerability arises due to the excessive time taken by UserAttributeSimilarityValidator to assess large passwords, allowing attackers to exploit this weakness in situations with unrestricted user registration.

Mitigation and Prevention

Protect systems from CVE-2021-45115 using the following strategies.

Immediate Steps to Take

Update Django to versions 2.2.26, 3.2.11, or 4.0.1 to mitigate the vulnerability.
Implement restrictions on user registration to limit potential attack vectors.

Long-Term Security Practices

Regularly review and update security configurations.
Monitor system resources and performance for unusual activity that may indicate a DoS attack.

Patching and Updates

Stay informed about security releases and promptly apply patches provided by Django to address vulnerabilities.