WordPress is popular and as it goes with all kinds of popular software, it becomes a target for hackers trying to take over and use your site to send spam into the world, or just cause some other kind of mayhem.

To protect yourself from this kind of trouble, there are a few things you can do to prevent bad things from happening to your precious WordPress site.

1. First, keep your WP software up-to-date. There are usually some security fixes in there and you do want to have those live on your public facing site. Hackers know what the vulnerabilities are in old WP versions and scan the internet automatically for unpatched sites. Don’t become an easy target by not having the latest version of WP installed. The latest version of WP (v3.7.1) is able to do security updates itself which is awesome. Be sure to check if your site supports this and activate it if it does.
2. Keep your plugins up-to-date as well for the very same reason. Old plugins can offer a way in for hackers, and we don’t want that to happen.
3. Delete (old) plugins you don’t use anymore, or replace them with newer ones. JetPack has a lot on board out of the box now so you can probably ditch a few old plugins. The fewer plugins you have, the less possible vulnerabilities your site has.
4. Take regular backups. In case something goes wrong, you can at least restore a version you know isn’t compromised.
5. Harden your WP site by configuring your .htaccess file if your site runs on an Apache web server. It’s explained nicely how to do that in the link. It can prevent hackers that do get access through a bad plugin to do any more damage to the rest of your site.
6. Use a long, hard to guess and preferably random password for your admin account. Using a different admin user is also a good idea. Brute force login attempts are made against the default “admin” user, so if that one has a long random password you’re pretty safe there. You can use something easier to remember for an alternative admin account if you want, but I recommend you to use something like KeePass to manage long & hard to guess passwords anyway.

Here are some plugins that can help with these tips:

• WordFence scans your site for possible vulnerabilities by checking your installed WP and plugin files with the ones from the official releases. It also helps with the first 2 tips by warning you by email if a plugin or WP itself needs an update. Quite handy.
• All In One WordPress security & Firewall plugin scans your site settings for security vulnerabilities and helps you get rid of them. It also has a firewall built in.
• WP security audit log won’t prevent anything, but it keeps track of logins, updates of plugins etc, so that if something weird happens, you can use it to figure out the “when” and “what”.
• A backup plugin. There are plenty and you should pick one that fits your needs. I’ve used BackUpWordPress for a DB backup only, but it can also backup the files. It emails you with either the zipped backup or a link to download it if it’s too big to stuff in the email. Another good option is UpdraftPlus which can backup your files & DB to remote storage like Google Drive or Dropbox a.o. Your hoster might also have a full backup feature, which is usually the best option anyway as it will backup more than just your WP site.
• BruteProtect protects (as it says) against brute force login attempts, a problem a lot of WP blogs had to deal with lately. Next to that you should of course make sure you have a complex password for your admin account.
• Bad Behavior is mainly a tool to combat spam, but since it scans for incoming malicious requests it can also block the occasional bot looking for vulnerable sites.

For a more extensive guide to securing your WordPress site, also check out this Bloggers Guide to WordPress Security. It’s long and full of great tips and guides covering a wide rang of security practices like how to combat spam, CAPTCHA’s and setting up HTTPS.