Solving Substantiation with SAML

Posted in security, f5, big-ip, ssl vpn, cloud, cloud computing, silva, application delivery, authentication, AAA, control by psilva on January 29th, 2013

Organizations are deploying distributed, hybrid architectures that can span multiple security domains. At any moment, a user could be accessing the corporate data center, the organization’s cloud infrastructure, or even a third party, #SaaS web application. #SAML can provide the identity information necessary to implement an enterprise-wide single sign-on solution.

Proving or asserting one’s identity in the physical world is often as simple as showing a driver’s license or state ID card. As long as the photo matches the face, that’s typically all that is needed to verify identity. This substantiation of identity is a physical form of authentication, and depending on the situation, the individual is then authorized either to receive something or to do something, for instance, enter a bar, complete a purchase, etc.

In the digital world, identity verification is not as easy as showing the computer monitor a driver’s license. To gain entry, you must provide information like a name, password, randomly generated token number—something you have, something you know, or something you are—to prove you are who you say you are.

Gaining access to corporate assets is no different. Many organizations have multiple different resource portals, however, each requiring digital proof of identity. Their users may also need to access partner portals, cloud based Software as a Service (SaaS) applications, or distributed, hybrid infrastructures that span multiple data centers, each requiring a unique user name and password. In addition, the average employee must maintain about 15 different passwords for both her private and corporate identities, with many of those passwords also being used for social media and other risky entities. Statistics show that 35 to 50 percent of help desk calls are related to password problems, with each call costing a company between $25 and $50 per request.

Security Assertion Markup Language (SAML) is an XML-based standard that allows secure web domains to exchange user authentication and authorization data. It directly addresses the problem of how to provide the users of web browsers with single sign-on (SSO) convenience. With SAML, an online service provider can contact a separate online identity provider to authenticate users who are attempting to access secure content. For example, a user might need to log in to Salesforce.com, but Salesforce (the service provider) has no mechanism to validate the user. Salesforce would then send a request to an identity provider, such as F5 BIG-IP Access Policy Manager (APM), to validate the requesting user’s identity. BIG-IP APM version 11.3 supports SAML federation, acting as either a service provider or an identity provider, enhancing the employee’s online experience and potentially reducing password-related tickets at the help desk.

BIG-IP APM version 11.3 can act as either a SAML service provider or a SAML identity provider, enabling both federation and SSO within an enterprise.

BIG-IP APM as a Service Provider

When a user initiates a request from a SAML IdP and the resources, such as an internal SharePoint site, are protected by BIG-IP APM, BIG-IP APM consumes that SAML assertion (claim) and validates its trustworthiness. This ultimately allows the user access to the resource. If the user goes directly to BIG-IP APM (as an SP) to access a resource (like SharePoint), then the user will be directed to the IdP to authenticate and get an assertion. Once a user is authenticated with a SAML IdP and accesses a resource behind BIG-IP APM, he or she will not need to authenticate again.

BIG-IP APM as an Identity Provider

Provided there is an SP that accepts assertions, a user can authenticate with BIG-IP APM to create an assertion. BIG-IP APM authenticates the user and displays resources. When the user clicks on an application, BIG-IP APM generates an assertion. That assertion can be passed on to the SP, which allows access to the resource without further authentication. When the user visits the SP first, the process is SP initiated; when the user goes directly to the IdP (in this case, BIG-IP APM) first to authenticate, the process is IdP initiated.

BIG-IP APM in a SAML Federation

SAML can be used to federate autonomous BIG-IP APM systems. This allows a user to connect to one BIG-IP device, authenticate, and transparently move to other participating BIG-IPs devices. Session replication is not part of SAML, but administrators can populate session information on participating systems. This means that BIG-IP device federation does not enable the use of a single session within the federation; it only enables information exchange among multiple members of the federation.  Each participating BIG-IP device maintains its own independent session with the client, and each has its own access policy that executes separately and independently.

Participating federation members can exchange information with any other federation members outside of sessions where needed. A common configuration is to have a dedicated BIG-IP device as a primary member to which users are authenticated and that provides information to other members. This allows a number of other BIG-IP devices to work in conjunction with that primary member.  The primary member is dedicated as an IdP, while the other participating members operate as SPs


The benefits of deploying BIG-IP APM as a SAML solution certainly include better password management, fewer help desk calls, and an improved user experience, but BIG-IP APM can also add additional context to requests. For instance, it can include endpoint inspection results as attributes to inform the application of the client’s security posture. In addition, IT administrators do not need to retrofit applications (e.g., .NET apps do not need a Kerberos claims plug-in). Another advantage is extensive session variable support, which allows organizations to

customize each user session. BIG-IP APM can bring SAML to resources and applications with minimal back-end changes—or none. These benefits all complement the values of BIG-IP APM to the overall traffic management of an organization’s IT infrastructure.

IT infrastructure has changed dramatically over the past few years, with many applications moving to cloud-based services. Corporate employees have also morphed into a mobile workforce that requires secure access to that infrastructure any time, from anywhere, and with any device. Bridging the identity gap between physically and logically separated services allows organizations to stay agile in this ever-changing environment and gives users the secure access they need around the clock.

BIG-IP APM version 11.3, in addition to delivering high availability and protecting organizations’ critical assets, provides a SAML 2.0 solution that offers the identity bridge needed to manage access across systems.



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