Cpanel FTP backup was detection as dos attack!!

Generally, servers that are identified as the source of malicious activity have been compromised, and the owner of the Linode isn't the person performing the reported activity. If you have been consistently backing up your cPanel files using FTP, it wouldn't suddenly be reported by someone else as malicious.

Personally, I would recommend using SFTP instead of FTP moving forward since SFTP necessitates a secure SSH connection. Otherwise, most system compromises can be prevented through good security practices. This can be anything from:

• Resetting the Root Password on your Linode | Linode to something complex and unique. Make sure to include capital and lowercase letters, numbers, and symbols and make sure the password is at least 12-16 characters longer (maybe even longer) to make the password harder to crack.
• Hardening SSH Access with Key-Pair Authentication
• Configuring a Firewall with UFW | Linode
• Installing Fail2ban to Secure Your Server (A Tutorial) | Linode

Scanning your server for Malware routinely is another great way to ensure that your system is safe and to identify and remove viruses if you have been hacked.

In cases where networking restrictions are enforced against your Linode, you can still connect to it using the LISH (Linode Shell) Console.

Alternatively, you can respond to the corresponding ToS Ticket about the matter with confirmation that you have Booted into Rescue Mode. This will allow us to temporarily remove those restrictions which will allow you to access your Linode to investigate.