At Cloudflare, we aim to make the Internet faster and safer for everyone. One way we do this is through caching: we keep a copy of our customer content in our 165 data centers around the world. This brings content closer to users and reduces traffic back to origin servers.
A few days ago, Cloudflare — along with the rest of the world — learned of a "practical" cache poisoning attack. In this post I’ll walk through the attack and explain how Cloudflare mitigated it for our customers.