CVE-2021-3908 : Security Advisory and Response

A deep dive into the CVE-2021-3908 vulnerability affecting OctoRPKI by Cloudflare, leading to infinite certificate chain depth.

Understanding CVE-2021-3908

This article explores the impact, technical details, and mitigation strategies related to CVE-2021-3908.

What is CVE-2021-3908?

CVE-2021-3908 in OctoRPKI allows an unrestricted certificate chain depth, permitting CAs to create unending child chains, causing perpetual tree traversal.

The Impact of CVE-2021-3908

The vulnerability poses a medium severity threat with a CVSS base score of 5.9, potentially leading to high availability impact.

Technical Details of CVE-2021-3908

Understanding the vulnerability description, affected systems, exploitation mechanism, and mitigation approaches.

Vulnerability Description

OctoRPKI lacks constraints on certificate chain depth, enabling CAs to generate child chains endlessly, resulting in infinite tree traversal.

Affected Systems and Versions

The vulnerability affects Cloudflare's OctoRPKI versions below 1.4.0 with custom configurations.

Exploitation Mechanism

Exploiting this flaw requires knowledge of certificate chain manipulation to induce perpetual chain traversal.

Mitigation and Prevention

Explore immediate steps, long-term security practices, and patching recommendations to mitigate the CVE-2021-3908 risk.

Immediate Steps to Take

Upgrade OctoRPKI to version 1.4 or above to prevent the exploitation of the infinite certificate chain vulnerability.

Long-Term Security Practices

Implement regular security audits, monitor certificate chains, and enforce depth restrictions to enhance RPKI security.

Patching and Updates

Stay informed about security advisories, apply patches promptly, and maintain a robust security posture to safeguard against potential vulnerabilities.