Please don't go blowing away your entire /etc/crontab! In most cases it isn't even necessary. As for their keys, they are locked down to a single IP address, s

Please don't go blowing away your entire /etc/crontab! In most cases it isn't even necessary. As for their keys, they are locked down to a single IP address, so unless the attackers gained control over that IP the attackers wouldn't be able to access your machine using those keys even if they were compromised.