MOST USEFUL SECURITY PLUGINS:

WordPress security is serious business. Exploits of vulnerabilities in WordPress’ architecture have led to mass compromises of servers through cross-site contamination. WordPress’ extensibility increases its vulnerability; plugins and themes house flawed logic, loopholes, Easter eggs, backdoors and a slew of other issues.

We'll provide list of plugins used for WordPress Security:

1) Bullet Proof Security

WordPress Website Security Protection. Website security protection against: XSS, RFI, CRLF, CSRF, Base64, Code Injection and SQL Injection hacking...

2) Better WP security

The easiest, most effective way to secure WordPress. Improve the security of any WordPress site in seconds.

3) Limit Login Attempts

Limit rate of login attempts, including by way of cookies, for each IP. Fully customizable.

4) Two factor authentication 

Easily add Duo Security two-factor authentication to your WordPress website. Enable two-factor authentication for your admins and/or users.

5) Theme-Check

A simple and easy way to test your theme for all the latest WordPress standards and practices. A great theme development tool!

6) Plugin-check

Simple tool to test all installed plugins using the tests provided by Theme-Check

7) Exploit Scanner

Search the files and database of your WordPress install for signs that may indicate that it has fallen victim to malicious hackers.

8) Theme Authenticity Checker

Scan all of your theme files for potentially malicious or unwanted code.

9) Akismet

Akismet checks your comments against the Akismet web service to see if they look like spam or not.