Authenticating in PHP using LDAP through Active Directory

Question

I'm looking for a way to authenticate users through LDAP with PHP (with Active Directory being the provider). Ideally, it should be able to run on IIS 7 (adLDAP does it on Apache). Anyone had done anything similar, with success?

• Edit: I'd prefer a library/class with code that's ready to go... It'd be silly to invent the wheel when someone has already done so.

Answer 1

Importing a whole library seems inefficient when all you need is essentially two lines of code...

$ldap = ldap_connect("ldap.example.com"); if ($bind = ldap_bind($ldap, $_POST['username'], $_POST['password'])) {   // log them in! } else {   // error message } 

Answer 2

You would think that simply authenticating a user in Active Directory would be a pretty simple process using LDAP in PHP without the need for a library. But there are a lot of things that can complicate it pretty fast:

• You must validate input. An empty username/password would pass otherwise.
• You should ensure the username/password is properly encoded when binding.
• You should be encrypting the connection using TLS.
• Using separate LDAP servers for redundancy in case one is down.
• Getting an informative error message if authentication fails.

It's actually easier in most cases to use a LDAP library supporting the above. I ultimately ended up rolling my own library which handles all the above points: LdapTools (Well, not just for authentication, it can do much more). It can be used like the following:

use LdapTools\Configuration; use LdapTools\DomainConfiguration; use LdapTools\LdapManager;  $domain = (new DomainConfiguration('example.com'))     ->setUsername('username') # A separate AD service account used by your app     ->setPassword('password')     ->setServers(['dc1', 'dc2', 'dc3'])     ->setUseTls(true); $config = new Configuration($domain); $ldap = new LdapManager($config);  if (!$ldap->authenticate($username, $password, $message)) {     echo "Error: $message"; } else {     // Do something... } 

The authenticate call above will:

• Validate that neither the username or password is empty.
• Ensure the username/password is properly encoded (UTF-8 by default)
• Try an alternate LDAP server in case one is down.
• Encrypt the authentication request using TLS.
• Provide additional information if it failed (ie. locked/disabled account, etc)

There are other libraries to do this too (Such as Adldap2). However, I felt compelled enough to provide some additional information as the most up-voted answer is actually a security risk to rely on with no input validation done and not using TLS.