Using active directory to authenticate users on intranet site

Question

I have an 'intranet' site that I have built, which has a login system of its own (users register as new users, and use the username/password thereon to login to the site). However, now I want to extend it, and have the intranet site use the existing ActiveDirectory for authentication. This is what I am looking for, going forward -

When a user access this intranet site (http://intranetsite/mySite), the user's domain credentials are validated against the active directory, and if the user's credentials match AD, the user is then presented the main page of the intranet site.

I am new to AD, and do not know how to go about this configuration. My intranet site is built around PHP and uses Apache on the application server; the AD is on a different IIS server.

What information do I need, and where do I put this information (into my site? htaccess? anywhere else?) so that I can use AD authentication? Is just 'configuration' enough, or do I need to write explicit PHP code for this authentication?

Any pointers are much appreciated.

Solution 1

If you are looking only for authentication and nothing else, you may get away with only a few lines of code.

First, ensure you have ldap enabled in your php.

Here's pure php implementation:
(note that when doing it this way you should ensure that you DO HAVE a username and a password from a user - anonymous binding will almost always return true for AD)

$link = ldap_connect('domain.com'); // Your domain or domain server

if(! $link) {
    // Could not connect to server - handle error appropriately
}

ldap_set_option($link, LDAP_OPT_PROTOCOL_VERSION, 3); // Recommended for AD

// Now try to authenticate with credentials provided by user
if (! ldap_bind($link, '[email protected]', 'SomeSecret')) {
    // Invalid credentials! Handle error appropriately
}
// Bind was successful - continue

If you expect to do more fun stuff with Active Directory like pulling some information about currently logged in user I strongly recommend using a framework to do the heavy lifting for you. As already mentioned, adLDAP is a good one and if you run PHP 5.4 I dare recommending the AD-X library which I actively develop (you can install it via Composer).

With the AD-X library, you can verify a user's credentials using this code:

try {
    $link = new ADX\Core\Link('domain.com'); // Establish connection to AD
    $link->bind('[email protected]', 'SomeSecret'); // Authenticate user
}
catch (ADX\Core\ServerUnreachableException $e) {
    // Unable to connect to server, handle error
}
catch (ADX\Core\InvalidCredentialsException $e) {
    // Invalid credentials supplied
}
catch (Exception $e) {
    // Something else happened, check the exception and handle appropriately
}

// Successfully authenticated if no exception has been thrown

Feel free to choose which suits you best. However, if you expect to do more than authenticate I strongly suggest you use a library for the ldap work - it will save you a lot of time and possibly frustration when things do not work as you would expect them to.

Also, if in doubt what information you can/should use to connect and to authenticate feel free to check my previous answer on this topic.

Solution 2

Here is what I use:

<?php
error_reporting(E_ALL);
ini_set('display_errors', 'On');

define('DOMAIN_FQDN', 'mycompany.intra');
define('LDAP_SERVER', '192.168.0.1');

if (isset($_POST['submit']))
{
    $user = strip_tags($_POST['username']) .'@'. DOMAIN_FQDN;
    $pass = stripslashes($_POST['password']);

    $conn = ldap_connect("ldap://". LDAP_SERVER ."/");

    if (!$conn)
        $err = 'Could not connect to LDAP server';

    else
    {
        define('LDAP_OPT_DIAGNOSTIC_MESSAGE', 0x0032);

        ldap_set_option($conn, LDAP_OPT_PROTOCOL_VERSION, 3);
        ldap_set_option($conn, LDAP_OPT_REFERRALS, 0);

        $bind = @ldap_bind($conn, $user, $pass);

        ldap_get_option($conn, LDAP_OPT_DIAGNOSTIC_MESSAGE, $extended_error);

        if (!empty($extended_error))
        {
            $errno = explode(',', $extended_error);
            $errno = $errno[2];
            $errno = explode(' ', $errno);
            $errno = $errno[2];
            $errno = intval($errno);

            if ($errno == 532)
                $err = 'Unable to login: Password expired';
        }

        elseif ($bind)
        {
            $base_dn = array("CN=Users,DC=". join(',DC=', explode('.', DOMAIN_FQDN)), 
                "OU=Users,OU=People,DC=". join(',DC=', explode('.', DOMAIN_FQDN)));

            $result = ldap_search(array($conn,$conn), $base_dn, "(cn=*)");

            if (!count($result))
                $err = 'Unable to login: '. ldap_error($conn);

            else
            {
                foreach ($result as $res)
                {
                    $info = ldap_get_entries($conn, $res);

                    for ($i = 0; $i < $info['count']; $i++)
                    {
                        if (isset($info[$i]['userprincipalname']) AND strtolower($info[$i]['userprincipalname'][0]) == strtolower($user))
                        {
                            session_start();

                            $username = explode('@', $user);
                            $_SESSION['foo'] = 'bar';

                            // set session variables...

                            break;
                        }
                    }
                }
            }
        }
    }

    // session OK, redirect to home page
    if (isset($_SESSION['foo']))
    {
        header('Location: /');
        exit();
    }

    elseif (!isset($err)) $err = 'Unable to login: '. ldap_error($conn);

    ldap_close($conn);
}
?>
<!DOCTYPE html><head><title>Login</title></head>
<style>
* { font-family: Calibri, Tahoma, Arial, sans-serif; }
.errmsg { color: red; }
#loginbox { font-size: 12px; }
</style>
<body>
<div align="center"><img id="imghdr" src="/img/logo.png" height="100" /><br><br><h2>Login</h2><br><br>

<div style="margin:10px 0;"></div>
<div title="Login" style="width:400px" id="loginbox">
    <div style="padding:10px 0 10px 60px">
    <form action="/login.php" id="login" method="post">
        <table><?php if (isset($err)) echo '<tr><td colspan="2" class="errmsg">'. $err .'</td></tr>'; ?>
            <tr>
                <td>Login:</td>
                <td><input type="text" name="username" style="border: 1px solid #ccc;" autocomplete="off"/></td>
            </tr>
            <tr>
                <td>Password:</td>
                <td><input type="password" name="password" style="border: 1px solid #ccc;" autocomplete="off"/></td>
            </tr>
        </table>
        <input class="button" type="submit" name="submit" value="Login" />
    </form>
    </div>
</div>
</div>
</body></html>

Comments

[DevlshOne]

While you certainly demonstrate how to connect and bind to AD with adLDAP this code includes so much advanced level code that it effectively conceals parts of code the asker is interested in most.

[Robert Rossmann]

My example does not demonstrate anything with adLDAP. Which part of it do you consider advanced and how would you recommend to update it? Thanks for explanation.

[Somnium]

How I can login user automatically? Your method requires username and password. How I can get those?