CVE-2021-23351 Explained : Impact and Mitigation

This article discusses the CVE-2021-23351 vulnerability found in the package github.com/pires/go-proxyproto before version 0.5.0 that can lead to Denial of Service (DoS) attacks.

Understanding CVE-2021-23351

This section provides insights into the vulnerability, impact, technical details, and mitigation strategies.

What is CVE-2021-23351?

The package github.com/pires/go-proxyproto before version 0.5.0 is susceptible to Denial of Service (DoS) attacks via the parseVersion1() function due to the lack of limits implementation.

The Impact of CVE-2021-23351

The vulnerability allows malicious actors to exhaust memory in server processes by sending deliberately malformed headers, leading to DoS attacks. However, the risk is limited as only trusted sources should send proxy protocol headers.

Technical Details of CVE-2021-23351

This section outlines the vulnerability description, affected systems, versions, and exploitation mechanism.

Vulnerability Description

The vulnerability can be exploited by sending a stream starting with PROXY and continuous data without newline characters until the target stops acknowledging.

Affected Systems and Versions

The vulnerability affects versions of github.com/pires/go-proxyproto that are older than 0.5.0.

Exploitation Mechanism

The vulnerability can be exploited by sending malicious streams to exhaust memory in server processes.

Mitigation and Prevention

This section provides guidance on immediate steps to take and long-term security practices to prevent such vulnerabilities.

Immediate Steps to Take

Users are advised to update to version 0.5.0 or newer to mitigate the vulnerability.

Long-Term Security Practices

Implement secure coding practices, perform regular security audits, and restrict access to trusted sources for sending proxy protocol headers.

Patching and Updates

Regularly monitor for updates and patches from the vendor to ensure system security.