@dave-r
There is no point in running a security plugin in a non secure WordPress release …
I mean, at least update WordPress to 3.5.2, and then still there have been so many security issues fixed in later major WordPress releases …
Best thing you can do is update to the latest WordPress release (4.7.1). No matter what …
@dave-r,
I would echo what @pronl said. WordPress 3.5.1 has 28 known security vulnerabilities. 3.5.1 is a 4 year old release…That’s ancient in internet time. There is no point in running a security plugin on a site like that. It won’t help.
Let’s put it this way: The only way to keep your site from being hacked is to upgrade it. There is no site that cannot be upgraded. If you don’t want to upgrade it, I would recommend shutting it down. Otherwise it’s only a matter of time until it gets hacked.