Hello,
That means that account on your server has been compromised, if you just migrate the server you will migrate it with the compromised account and script and will have the same problem on the new host. This will cost you a lot of money down the road in bandwidth overage charges cause the script is just eating your bandwidth. What needs to be done is the account needs to be traced, script removed, account secured and server will be brought back online. We can do that over the KVM console.