mTLS: When Certificate Authentication Done Wrong
Michael Stepankin analyzes implementation flaws in mutual TLS (mTLS) certificate authentication, detailing CVEs in open-source identity servers leading to impersonation.
Summary
The Growing Adoption of Mutual TLS in Zero-Trust
Mutual TLS (mTLS) has become the gold standard for zero-trust client authentication and service-to-service communication, replacing passwords with cryptographic X.509 certificates.
Implementation Flaws in Certificate Validation Logic
Michael Stepankin reveals that parsing and validating client certificate attributes in application code frequently introduces critical logic vulnerabilities.
Exploiting User Impersonation and Privilege Escalation
Analyzing real-world CVEs in popular open-source identity providers and reverse proxies demonstrates how attackers can forge SAN attributes and bypass authorization filters.
Secure Code Patterns for X.509 Verification
Stepankin provides concrete source code examples and architectural guidelines for securely handling client certificates, sanitizing proxy headers, and validating certificate chains.
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