Today, like the past few days, we have had some downtime. Apparently some script kids are enjoying themselves by targeting our server (and others). Sorry for the inconvenience.
Most of these 'attacks' are targeted at the database, but some are more ddos-like and can be mitigated by using a CDN.
Some other Lemmy servers are using Cloudflare, so we know that works. Therefore we have chosen Cloudflare as CDN / DDOS protection platform for now. We will look into other options, but we needed something to be implemented asap.
For the other attacks, we are using them to investigate and implement measures like rate limiting etc.
How does cloudflare work? Do you install the private SSL certificate there and so cloudflare can see all traffic, including passwords, in plain text or is the path from browser through to your server still encrypted?
Cloudflare is a proxy, so by its very nature it has to decrypt traffic. (I believe their enterprise plans may offer a way around this, but don't quote me.)
I wouldn't worry, however. If someone wanted to attack this site (or any site, really) they're almost certainly going to have an easier time going after the origin rather than trying to take on a juggernaut like Cloudflare.
Other posters are correct that cloudflare decrypts traffic. BUT it is highly unlikely that they will see your password in plaintext, since it is best practice to hash the password first on the front-end.