🛡️ Security

ASN.1

Abstract Syntax Notation One, a standard for describing structured data as tag-length-value elements. X.509 certificates are ASN.1 encoded, so every TLS and IPsec endpoint contains an ASN.1 decoder that runs on untrusted input, a frequent source of memory-safety bugs.

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Why VPN Certificate Parsing Is Pre-Authentication Attack Surface

A VPN gateway must decode a peer's certificate before it can trust the peer. That ordering makes the ASN.1 parser reachable by anyone on the internet, and it is where two classic bug types live.

intermediate 6 min read

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