Web Access Management Monitoring with Nagios and CkFormLogin

2006-09-10 20:00:00 -0400


There is no question that Access Management systems provide a host of benefits to the users and maintainers of web applications in large-scale environments. Yet, adding an access management system can also introduce a set of new potential points of failure. Even though infrastructure may be designed to maximize fault tolerance there is still risk because many security “eggs” are now in one basket. Systematic failure of any single component (LDAP directory, Virtual Directory, Access / Policy Server, web/application server plug-in, application integration code, etc.) can render applications unusable. As a result, system monitoring is often one of the most critical considerations in an Access Management deployment.

Thankfully, there are a number of network monitoring solutions that are capable of automatically monitoring applications and issuing notifications when a service become unavailable. We particularly like the open source Nagios system because it’s easily extensible, feature rich, and low cost. In order to make it more useful in the context of Access Management deployments we’ve developed a Nagios plug-in called CkFormLogin that monitors every point in the simple form login process common to most Access Management systems:

  1. Initial request for a protected website URL – CkFormLogin verifies that the initial request receives a redirect to the login page.
  2. Login page availability – CkFormLogin follows the redirect and performs a content check on the login page to ensure that it is accessible and no errors are returned.
  3. Authentication – After login page verification CkFormLogin issues an HTTP Post request with the username, password, or any other credentials to a configurable authentication URL. This step tests the functionality of a web server plug-in like a WebGate, Web Agent, or Policy Agent and implicitly verifies the availability and functionality of any policy/access servers, LDAP directories and other supporting infrastructure components.
  4. Content check – Assuming that authentication has succeeded CkFormLogin will follow the redirect back to the requested page and execute a custom content check on the page. By checking for the presence of some personalized text, or other identity specific data, the plug-in assures that application components have properly recognized and authorized the test user at runtime.
In short, this process provides a high level of assurance that secure/protected sites, and all of their externalized security dependencies, are actually available and functional to end-users. If any step in the login, authentication or authorization process fails the plug-in will return an error and the appropriate support staff can be notified by Nagios based on its configurable notification rules. When used in conjunction with other Nagios plug-ins for TCP/IP socket connections, LDAP, and HTTP services it can even help to pinpoint the root cause of a failure before a support technician even starts to troubleshoot.

The plug-in itself was written to validate the form login features of Oracle COREid Access Manager, but should also work with the usual suspects (Siteminder, Sun Access Manager, custom form based authentication) without significant modification. Its simple to install, requiring only Nagios, Perl and a few CPAN libraries. Like Nagios, CkFormLogin is released as open source software under the GNU Public License. Feel free to check it out.


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