Curtiss Grymala

This plugin allows WordPress to authenticate, authorize, create and update against an Active Directory domain. This plugin is based heavily on the <a href="https://wordpress.org/extend/plugins/active-directory-integration/" rel="ugc">Active Directory Integration</a> plugin, but has been modified to work with Multi Site and even Multi Network installations of WordPress.
Some of the features included in this plugin are:
<ul>
<li>authenticate against more than one AD Server (for balanced load)</li>
<li>authorize users by Active Directory group memberships</li>
<li>auto create and update users that can authenticate against AD 
mapping of AD groups to WordPress roles</li>
<li>use TLS (or LDAPS) for secure communication to AD Servers (recommended)</li>
<li>use non standard port for communication to AD Servers</li>
<li>protection against brute force attacks</li>
<li>user and/or admin e-mail notification on failed login attempts</li>
<li>determine WP display name from AD attributes (sAMAccountName, displayName, description, SN, CN, givenName or mail)</li>
<li>enable/disable password changes for local (non AD) WP users</li>
<li>WordPress 3.0/3.1 compatibility, including Multi Site and Multi Network</li>
</ul>
This plugin is based on <a href="https://wordpress.org/extend/plugins/active-directory-integration/" rel="ugc">glatze’s Active Directory Integration</a> plugin, which is based upon <a href="https://wordpress.org/extend/plugins/active-directory-authentication/" rel="ugc">Jonathan Marc Bearak’s Active Directory Authentication</a> plugin and <a href="http://adldap.sourceforge.net/" rel="nofollow ugc">Scott Barnett’s adLDAP</a>, a very useful PHP class.
Aside from the changes to make this plugin work more effectively with WordPress Multi Site, this version of the plugin also encrypts the password used to connect to the AD server when it is stored in the database.
This plugin was developed by <a href="https://wordpress.org/extend/plugins/profile/cgrymala" rel="ugc">Curtiss Grymala</a> for the <a href="http://umw.edu/" rel="nofollow ugc">University of Mary Washington</a>. It is licensed under the GPL2, which basically means you can take it, break it and change it any way you want, as long as the original credit and license information remains somewhere in the package.
<h3>Important Notice</h3>
Since I don’t currently have access to multiple AD servers, this plugin has only been tested on a single installation of WordPress with a single AD server. Therefore, it is entirely possible that there are major bugs.
At this time, I am seeking people to test the plugin, so please report any issues you encounter.
<h3>Requirements</h3>
<ul>
<li>
This plugin requires WordPress. It might work with versions older than 3.0, but it has not been tested with those.
</li>
<li>
This plugin also requires PHP5. Some attempt has been made to make it compatible with PHP4, but it has not been tested in that environment.
</li>
<li>
This plugin requires LDAP support to be compiled into PHP. If the <code>ldap_connect()</code> function is not available, this plugin will output an error message and will not do anything.
</li>
</ul>
<h3>To Do</h3>
<ul>
<li>Add ability to validate against multiple AD servers (check one, then the other – rather than just load-balancing as the plugin currently does)</li>
<li>DONE as of 0.4a – Update admin interface to utilize native meta box interface rather than custom layout</li>
<li>DONE as of 0.3a – Separate the profile information from the role equivalent groups in the “auto update user” setting</li>
</ul>

Active Directory Authentication Integration

Allows WordPress to authenticate, authorize, create and update users through Active Directory

drahkar

This plugin allows WordPress to authenticate users against an Active Directory. 
Developed to be compatible with current Active Directory releases as well as allow 
for Enterprise level Forest Deployments by allowing you to enter custom BaseDNs.
If you have bugs, suggestions, desires or requirements that you would like to see added 
to this, please come to the plugin page and submit them there so I can keep track 
of them as they are found and resolved.
This plugin is redeveloped off of <a href="https://wordpress.org/extend/plugins/simple-ldap-authentication/" rel="ugc">Simple LDAP 
Authentication</a>.
<h4>How to use</h4>
You can use this plugin in a few different ways.
<ol>
<li>
You can create WordPress accounts which match the names of your Active Directory accounts, and create these users from within the WordPress Users panel. Only the users you create in WordPress will be able to log in.
</li>
<li>
You can tick a checkbox so that anyone who can authenticate via Active Directory can log on. A WordPress account will be automatically created for the user if one does not already exist, with the default user role.
</li>
<li>
You can list the names of Active Directory groups who you want to allow to log on to WordPress. For each group in Active Directory, you can specify a corresponding WordPress user role.
</li>
</ol>
You can also combine the above however you like.

Simple AD Authentication

Authenticates users through Active Directory.

Active Directory Authentication Integration vs Simple AD Authentication