Samuel Proulx

Or they live in a country where genocide denial is legal. I live in Canada and my server is in Canada. I’m not willing to take the risk so my users can interact with assholes.

All responsible server admins have them defederated. Hate speech and genocide denial, that is almost certainly against the law in Canada, Germany, and other places. We defederated lemmygrad for the same reason.

So most modern activitypub servers backfill threads and profiles. My single user instance processes 30000 notes a day. If I was actually trying, I’m sure it’d be easy to grab much more while appearing well behaved.

How does that help? My personal instance currently has a database of several million posts thanks to the various Mastodon relays. I don’t need to scrape your instance to sell your posts. I don’t, of course, but it’d be easy for some company to create friendlycutekittens.social and just start collecting posts. Do you really have time to audit every instance you federate with?

From the article:

The TLS-SNI header is used by CDN servers to route requests based on the Server Name in the header. However, a typical front end server, or even a load balancer (LB), belongs to a single app or organization, and does not typically need to handle the SNI header. The easy and reasonable way to configure TLS certificates on such a server, is to either:
 Serve all requests with a single TLS certificate that has SANs (Subject Alternative Names) for all the domains that are used Have multiple certificates, chosen according to SNI, with one of them as the default. In both of these common cases, sending a HTTPS request directly to the IP of a front end server, without any SNI, will present us with a default server certificate. This certificate will reveal what domains are being served by this server.

So apparently the real issue is that people aren’t using SNI correctly.

The tech blog is much better: https://www.zafran.io/resources/breaking-waf-technical-analysis

It boils down to scanning all IPV4 space, and grabbing the SSL certificate returned by any webservers on port 443. If the server is incorrectly configured the fields in the SSL cert will tell you what domains it serves. And using Certificate Transparency logs to figure out what domains you want to target. I wouldn’t really call this a flaw that breaks anything. It’s just a byproduct of how SSL, IPV4, and WAFs work.

Your post showed up here just fine.