Ask HN: Media Temple

I run 2 web sites that use Wordpress (latest versions) with mediatemple.net and I keep getting hacked with an iframe insert. It installs malware on visitors computers.

Can anyone tell me what steps they take to ensure that wordpress is 100 percent secure from attacks (or at least 99.9 percent)?

I have tried changing the file attributes to 444 but that has not worked.

Any feedback will be helpful.

Thanks.