Will an SSL certificate prevent cPanel hacks?
If the problem is that somebody intercepts your password by sniffing the unencrypted network traffic then using SSL will help. This means not just installing a SSL certificate but actually using https:// instead of http:// to access the site.
If the problem is instead a security issue of cPanel or that the attacker grabs your login credentials on your own machine (malware, malicious browser plugin or similar) then SSL will not help since it only protects the transport of the data between browser and server.
What an SSL cert does
By default, logins can be intercepted at any point, on your computer, in between the computer and server, or on the server.
Using an SSL connection protects the traffic from your computer to the server, but it does not protect from malware at either end of the connection, and if you use a service like Cloudflare you may not be protected from the service to the origin server.
Will an SSL certificate prevent this?
It depends how the credentials are being captured, if your host or machine are compromised then it might not help, but it will reduce the attack surface of your site, this is why chrome now shows warning for insecure logins, because the extra risk of using HTTPS has near to no advantage.
Sources
- Google post on
not-securemessage - IsTLSFastYet (shows the drawbacks of SSL are small)