CVE-2021-29431 Explained : Impact and Mitigation

Sydent, a reference Matrix identity server, is susceptible to a Server-Side Request Forgery (SSRF) vulnerability due to missing validation of hostnames. This can lead to internal systems being induced to send HTTP GET requests via SSRF.

Understanding CVE-2021-29431

This article discusses the impact, technical details, and mitigation strategies for the SSRF vulnerability present in Sydent.

What is CVE-2021-29431?

Sydent lacks proper validation of hostnames, allowing attackers to trigger HTTP GET requests to internal systems through SSRF.

The Impact of CVE-2021-29431

The vulnerability poses a high severity risk with a CVSS base score of 7.7, primarily affecting confidentiality due to potential data leaks.

Technical Details of CVE-2021-29431

The following section outlines the specific aspects of the vulnerability.

Vulnerability Description

Sydent's SSRF flaw enables attackers to initiate HTTP requests impacting internal systems.

Affected Systems and Versions

Sydent versions prior to 2.3.0 are affected by this SSRF vulnerability.

Exploitation Mechanism

Exploiting the vulnerability involves inducing Sydent to send HTTP GET requests to internal systems through SSRF.

Mitigation and Prevention

Discover the measures to prevent and address the SSRF vulnerability in Sydent below.

Immediate Steps to Take

Consider implementing firewall rules to restrict Sydent's access to internal HTTP resources.

Long-Term Security Practices

Regularly update Sydent to the latest version and perform security assessments to identify SSRF vulnerabilities.

Patching and Updates

Ensure timely application of patches released by Matrix-org to address the SSRF vulnerability in Sydent.