How to protect the site from overload on shared hosting?

Question

Apache HTTP Server

Greetings!
There are several sites on the standard shared hosting plan. Never had an overload. For some 20 minutes of scanning by the Wpscan service, the load on the server increased 8 times! All requests went to a redirect. In a second about 10. A letter came about exceeding the load.
Example:

11.111.111.11 - - [17/Feb/2017:18:20:38 +0300] "GET /backup/admin HTTP/1.1" 301 - "-" "

Temporary solution to block IP. Well, actually the question is:
How to protect sites from hooligans who will abuse this and similar tools to "put" the site? Indeed, in this way, in a couple of days, the provider will turn off the sites due to the load.
Sites on Wordpress, I try not to use plugins.

Answer 1

Before connecting something from third-party services , I advise you to first understand as much as possible:
1. With a description of the problem
2. With the conditions for its occurrence
3. With the consequences caused by it
4. With ways to prevent the occurrence of a problem
5. With ways to eliminate an already existing problem for the minimum time
There are settings for the number of connections, the frequency of connections (frequency of requests), the order of transitions.
For very active - first shaper, then captcha, then temporary ban, then permanent.
Choose!)))
CP - payload in minutes: the amount of work of one core for 60 minutes (hour) is calculated: 1 core working for a whole hour = 100% load.
CP=60*T/60 ,
where T is the number of minutes of useful processor time per core.

Answer 2

Buy vps and deploy sites there

Answer 3

Connect CloudFlare