Protocols, security incidents, and how the internet actually works. 147 posts.
To save a round trip, your browser lets a server recognize it on the next visit — at the TLS layer, below the cookie jar. For years that optimization was a supercookie, and the story of how it got fixed is a lesson in where identity really leaks.
No password was stolen and the registrar record never changed. Yet tens of thousands of domains were taken over — because they pointed their DNS at a provider that would hand the zone to anyone who asked.
No server was breached. In February 2024 a company bought the polyfill.io domain, and four months later it was quietly serving malware to over 100,000 sites. The attack was the purchase.
For nearly two years, every key generated with OpenSSL on Debian and Ubuntu could be picked from a list of 32,767 — because a cleanup meant to silence a memory-checker warning deleted the line that stirred in the randomness.
DNS makes you know a name before you can ask about it — you can't list a zone. Except there's one operation that lists the whole thing, AXFR, and when it's left open a stranger can ask a nameserver to mail them the phone book.
In 2014 a missing bounds check in OpenSSL let anyone ask a server for 64KB of its own memory — private keys, passwords, session cookies — and the request looked exactly like a normal heartbeat, so no server could tell whether it had been robbed.
The trailing dot is the most technically correct way to write a domain name — it spells out the DNS root. Every layer above DNS disagrees about what it means, and those disagreements keep turning into security bugs.
A national firewall doesn't block a censored DNS lookup — it answers it, with a forged reply that wins a race against the truth. Sometimes the lie points at a real company's server, and sometimes it leaks to people the censor never meant to reach.
For eight years the security of signed DNS hung from a single key that had never once changed. When they finally rolled it in 2018, the terrifying part wasn't the cryptography — it was that nobody could see which resolvers were ready to follow.
In 2017 a single wrong comparison in a Cloudflare parser let a pointer run off the end of a buffer and dump adjacent memory into web pages — so one site's requests could surface another site's passwords, and search engines cached the spills.
In 2012 an espionage toolkit pushed itself onto machines as a signed Windows Update. To sign it, the operators forged a Microsoft certificate with an MD5 collision no academic had published yet — the last link in a chain of institutional mistakes that all had to line up.
In 2023 researchers showed they could silently delete a message from the start of an SSH session — and the cipher that made it cleanest was chacha20-poly1305, the one every hardening guide told you to prefer. The bug wasn't in any server. It was in the seam the protocol never checked.