Web Application Login Integration with APM

As we hurtle forward through the information age we continue to find ourselves increasingly dependant on the applications upon which we rely. Whether it's your favorite iPhone app or the tools that allow you to do your job, the applications that you interact with and the information contained within are a sacred thing to the average IT warrior. As such, we hold the security of said applications and data in high regard. This leads to entire security teams dreaming up more complex ways to protect your information along more hoops for you to jump through to gain access. Their intentions are pure and the added barriers to entry by way of complex login processes, password security requirements, access enforcement, etc. are justified, but that makes them no less cumbersome.

For the remote users the saga is even worse. While the local application user gripes about the latest policy enforced for their own good by the security team the remote user deals with the same restrictions and then some, often including the added step of having to "remote in" via VPN of some sort before even being allowed access to the resources they require. Fortunately though, it doesn't have to be this way.

One of the many features F5's Access Policy Manager (APM) offers is seamless integration into your existing application or portal. By configuring APM to accept credentials passed via a simple POST from any application, it can truly be a transparent gateway into your authentication infrastructure. With this configuration, whether the user is internal or external, simply logging into the portal/app in question will pass their credentials to APM which can them seamlessly assign them to the appropriate resources, granting or limiting their access as necessary.

The setup is simple. Let's walk through it, assuming we have a basic Virtual IP set up on the APM, and our application has a simple login form, something like:

Note that the action on the above form is https://10.10.12.8/fake. This is a "fake" URI on the APM device that's going to be doing the heavy lifting here (The Virtual Server's IP on the APM is 10.10.12.8).

The form will look like you would expect, like this:

Now that we have a form to play with we'll need to capture the credentials being passed when a user submits the form to log in. This is done via a simple, flexible iRule. We'll input the "/fake" as the URI we're searching for, then do some straight-forward logic to identify the username and password in the POST from the form. Once we have that data singled out, we'll store it in session variables for later use in APM's auth process. The whole thing looks like this:

Once the iRule is created and assigned to the APM virtual (10.10.12.8, from above) we should have the data collected and stored as needed. Next we need to instruct APM to access those session variables we set earlier. To do so we'll use the Visual Policy Editor built into APM to make constructing login flows simple. First add an empty event to check for the credentials. We'll call that "have creds". Next, be sure you have some form of authentication set up to actually authenticate the credentials passed in via the form once the "have creds" event succeeds, otherwise anyone will be able to log in, and that's not what we're looking for. For that we've set up a standard AD Auth event in APM which will fire and perform the actual authentication step once we've successfully collected the data from the POST. The setup in the VPE should look something like this:

Now that we have the basic structure in place, let's make it do something. Create a new Branch Rule (also named have creds for this example, appearing on the line between have creds and AD Auth) that makes use of an advanced check. We'll tell it to look for the session.logon.last.username variable that we set in the iRule to ensure that the rule was successful.

If this check is successful it means that the iRule found a username in the POST from the form and we can safely pass the username and password variables on to the AD Auth event for processing. So, assuming the username and password entered in the original HTML form are correct, once you hit "Logon" to submit the form, your information will be passed back through APM for authentication via AD, and then assigned whatever resources are deemed appropriate for that user based on the "Resource Assign" action.

There you have it, login integration to assign resource access. This could of course be done with any login form, not just the simple HTML example above, to save users one more hoop to jump through before getting access to the applications they depend on.