John Godley

HTML Purified replaces the default WordPress comments filters with HTML Purifier, a super HTML filtering 
library.
<blockquote>
HTML Purifier is a standards-compliant HTML filter library written in PHP. HTML Purifier will 
 not only remove all malicious code (better known as XSS) with a thoroughly audited, secure yet 
 permissive whitelist, it will also make sure your documents are standards compliant, something 
 only achievable with a comprehensive knowledge of W3C’s specifications.
</blockquote>
An additional feature of HTML Purifier is that it will produce valid well-formed XHTML code, something 
which KSES does not do.
Features:
<ul>
<li>Configurable KSES or HTML Purifier</li>
<li>Configurable list of HTML elements and attributes for both KSES and HTML purifier</li>
<li>Additionally process comments with HTML Tidy</li>
<li>URL blacklist</li>
<li>Fully localized (and awaiting translations)</li>
<li>Automatically escape PHP or anything inside backticks</li>
</ul>
HTML Purifier is available in:
<ul>
<li>English</li>
<li>Spanish, thanks to José Cuesta</li>
<li>Belorussian, thanks to Marcis Gasuns</li>
<li>Russian, thanks to Ilyuha</li>
<li>Uzbekistan, thanks to Alexandra Bolshova</li>
<li>Dutch, thanks to Pieter</li>
<li>German, thanks to Andreas Beraz</li>
<li>Polish, thanks to Kasia Ciszewski & Dawid Śpiechowicz</li>
<li>Romanian, thanks to Alina @ InboxTranslations.com</li>
<li>Lithuanian, thanks to Nata Strazda</li>
<li>Ukranian, thanks to Iflexion Design</li>
</ul>
<h3>Documentation</h3>
Full documentation can be found on the <a href="http://urbangiraffe.com/plugins/html-purified/" rel="nofollow ugc">HTML Purified</a> page.

HTML Purified

HTML Purified replaces the default comments filters with the more secure HTML Purifier.

zackdesign

AliasIO

Note: This plugin requires PHP 5
Using WordPress security docs as a guide we have targeted a lot of the issues and endeavoured to make the process of strengthening your WP installation as easy as possible by providing the information you need to be able to set things up.
Features:
<pre><code>* Scan the database for possible XSS issues.
* Limit login attempts to one per ten seconds per user.
* Check all file permissions.
* Check for presence of index.html files in all directories.
* Check if WordPress is up-to-date.
* Remove the version number from HTML source.
* Log all POST requests.
* Log all failed login attempts.
* Change the admin username.
* Randomize the database table prefix.
* Require stronger passwords.
* Detect SSH.
</code></pre>
This plugin was commisioned by <a href="http://www.michaelpenner.com/" title="MJ Penner Consulting" rel="nofollow ugc">MJ Penner Consulting</a> and released to the general public as a gesture of good will.

MJP Security Plugin

MJP Security Tools is a plugin designed to fix a lot of Wordpress security issues, as well as providing extra support.

HTML Purified vs MJP Security Plugin