Trapped By The CLI - Vulnerability in TLS/SSL Cryptographic Toolkits

This conference talk reveals how William Robinet discovered a vulnerability common to various TLS/SSL cryptographic toolkits by chance. Learn about his ASN.1 templating tool, a primarily Perl script that converts the output of OpenSSL's `asn1parse` command into a textual description for reconstructing original ASN.1 structures. Discover how this tool helped identify an issue in OpenSSL CLI applications, and explore how this vulnerability extends to other cryptographic toolkits. Understand how these issues can be exploited to trap administrators who are unaware of the vulnerability. The presentation was delivered at Nullcon Goa 2025 and runs for 38 minutes.