To whomever owns this server. I do sincerely apologise. Your server has been responsible for brute forcing the SSH of other servers all over the net. Please do not worry, this is not really your fault. Whoever did this installed malware known as 'Alfa Team: Hidden Shell' and 'Dhanush'. Feel free to Google them.
We are not hackers ourselves, but we took advantage of your servers lack of security to remove the hackers files and to try and secure it as best as we can. For example; Your upload scripts were unfiltered and were used to upload malware. You need to do a better job at securing these scripts to prevent the unauthorised upload of malicious PHP files. Ideally you want it to only accept certain files (IE; a Whitelist) such as MP3, OGG, TXT, JPG, etc. Certainly not HTML or PHP.
Additionally I would advise that you look into something called CSF (Config Server and Firewall); please note that we are not affiliated to them, nor do we represent them. But they are a good layer of defence against these kinds of attacks. There is plenty of documentation online about how to properly configure it, and CSF do a very good job at explaining the installation process, unlike certain webservers.
Lastly; I can't recommend enough to look into Hardening (security) such as PHP Hardening, Apache Hardening, and so on. Again; a good search engine is your friend here. If you are using default passwords for anything, please change them immediately and do not use easy to guess passwords like "Password".
I want to reiterate that we didn't hack your server, we deleted the hackers files and have tried our best to secure it as best as we can for the mean time in the only way we really know how. They may already have backdoor access (Like setting up Shell Users in SSH, which we urge you to check.) To secure this server, I've had to fill up your server with Animoo and Furry porn. They can't upload anything if there is no space to upload anything, and I have terabytes of animoo and furry porn. We did try other avenues, but this was all we could do. We apologise if this offends your sensibilities.
- Your friends, The Grey-Hat Degenerates