CVE-2021-21328 : Security Advisory and Response

A denial of service vulnerability (CVE-2021-21328) has been discovered in Vapor, a web framework for Swift. The vulnerability allows attackers to conduct a DoS attack by sending unlimited requests against a Vapor instance with different paths, leading to system drain and potential impact on downstream services.

Understanding CVE-2021-20657

This section provides detailed insights into the nature and impact of the denial of service vulnerability in Vapor.

What is CVE-2021-21328?

CVE-2021-21328 is a DoS vulnerability in Vapor web framework that enables attackers to overload the system by sending unlimited requests, potentially affecting system performance.

The Impact of CVE-2021-21328

The vulnerability can lead to system resource exhaustion and impact the availability of both the Vapor instance and downstream services, causing disruptions.

Technical Details of CVE-2021-21328

This section delves into the technical aspects of the CVE, including how the vulnerability can be exploited and the affected systems.

Vulnerability Description

In Vapor versions <= 4.40.0, attackers can exploit the DoS vulnerability by overwhelming the system with unlimited requests, leading to resource depletion.

Affected Systems and Versions

The vulnerability affects Vapor instances running versions lower than 4.40.1. Systems with these versions are susceptible to the DoS attack.

Exploitation Mechanism

Attackers can exploit this vulnerability by targeting Vapor instances with unlimited requests, creating excessive counters and timers that consume system resources.

Mitigation and Prevention

This section outlines the necessary steps to mitigate the impact of CVE-2021-21328 and prevent future occurrences of similar vulnerabilities.

Immediate Steps to Take

Users are advised to update their Vapor installations to version 4.40.1 or higher to patch the vulnerability and prevent exploitation by malicious actors.

Long-Term Security Practices

Implementing secure coding practices, monitoring system resources, and conducting regular security audits can help enhance the overall security posture.

Patching and Updates

Regularly updating Vapor frameworks and applying security patches promptly can help mitigate the risk of exploitation and ensure a more secure environment.