Bottom line is, unless your site is build with custom php it will get hacked.
Wordpress, Joomla are very hackable no matter if you took measures to protect yourself
My sites got hacked and my ranking dropped. I'm still trying to estimate the extent to which google has panelized me. Basically like 4 of my websites have malware. If anybody can shed some light on what being reported by google as "spammy" due to malware attacks does to you, it would be great...
Only a few weeks ago did I pay a freelancer to remove malware from another attack, I then installed a wordpress firewall .. "Trying not to laugh" that I thought was gonna protect me.
So basically when you get a dedicated server, you get no protection at all.. and you're responsible for monitoring your security and your files unlike with the cheaper and standard option called "shared hosting".
Then if you want security for your dedicated server you need to sign up with "Sitelock", which will protect you with a cost of 200$ / website.. yearly..
Bottom line is that, dedicated servers can mess up your ranking due to the almost guaranteed hacker attacks you will get. So watch out!