Welcome!

Microservices Expo Authors: Stackify Blog, Elizabeth White, Dalibor Siroky, Pat Romanski, Liz McMillan

Related Topics: Microservices Expo

Microservices Expo: Article

Identity Propagation in a SOA

The shortcomings of current solutions

One of the challenges IT organizations face is how to propagate identities in complex business processes that are commonly found in Service Oriented Architectures (SOAs). Identities, which are passed from one service invocation to the next in a business process, give the process a user context. Identities can be used to determine access rights to SOA services and for audit and compliance purposes.

For example, consider a procurement business process for an application that's used by a number of purchasing agents. Each agent has a different purchasing privilege. Say a senior agent can purchase up to $50,000 in a transaction, while a junior agent can buy only $25,000. If the business process that enables the purchase is composed of a number of SOA services, each service must know the user's identity to enforce purchasing privileges.

This article shows the need for identities in an SOA, provides examples of SOAs, and reviews the status and shortcomings of current solutions.

Introduction to Identity Propagation
Before we look at identity propagation in an SOA, let's look at it in a three-tier environment, where it's easier to illustrate the basic concepts. Once again, we'll use the procurement application scenario - except this time, the application resides in a Web-based portal instead of being loosely coupled in an SOA.

The presentation and logic tiers exist in the portal application server and the data tier resides in the database. The identity of a procurement agent is established when the user starts accessing the portal application from the Web browser and the identity spans all three tiers of the portal. This identity is used for authentication and authorization purposes throughout the business processes tha span the portal. Identity propagation in this case spans from the Web browser, to the portal, to the backend database (see Figure 1).

To fully illustrate identity propagation, let's dig deeper into this scenario and see how the identity is propagated. The procurement application, which sits in the portal, requires the user to log in to gain access. When the agent initially accesses the portal, the portal presents a JSP- or HTML-based form that requires a username and password. These credentials are sent over an encrypted SSL channel to prevent anyone from sniffing the password over the wire.

Let's assume that the portal is running in a J2EE application server. The application would typically use a Java Authentication and Authorization Service (JAAS) login module to process the username and password, and then authenticate and authorize the user. The username and password credentials are checked against an LDAP directory, or perhaps an identity management infrastructure. If the login is successful, a JAAS subject is created in the current execution context of the J2EE portal. This object is used to identify the user in the J2EE container.

The subject is used to authorize any subsequent requests from the user to a secured resource in the application server. For example, the secured resource may be an Enterprise Java Bean (EJB) that accesses the portal's backend database. The subject is used to determine if the user should have access to the EJB. The user identity could also be propagated to the database using proprietary techniques such as impersonation, which could be used to determine if the user should have access to the backend data.

Figure 2 shows how an identity can be passed from the browser to the backend database. The identity is first passed from the browser to the portal application. From there, it can be propagated to EJBs or databases. At each step, the identity is bound to the resource. For example, JAAS is used to bind the identity of the portal user to an executing thread in the portal procurement application. This way, the user's identity can be used to determine access to subsequent resources.

The identity can also be used for audit and compliance purposes. The portal can set alerts for authentication or authorization failures in the banking application or database. Useful data can also be mined based on the user identities passing through the portal. For example, the bank could determine if purchasing agents are trying to exceed their purchasing limits.

Identities in an SOA
In our example, the techniques used to propagate identities are often proprietary or non-standard. This works well in closed environments, but in heterogeneous environments where services must be interoperable, proprietary techniques fall short. SOAs are typically composed of multi-vendor heterogeneous environments.

Think of an SOA as an evolution of the three-tier architecture where applications, like the portal, are loosely coupled applications built as a collection of services. The idea is to expose business logic as services in a reusable and interoperable fashion. For example, a service could:

  • Return a list of items that can be purchased
  • Return the status of a purchase order
  • Submit a purchase order.
SOA services aren't necessarily uniform. For example, they could be exposed through different types of protocols such as JMS, REST, RMI, .NET Remoting, MQSeries, or SOAP (see Figure 3).

These services can also be orchestrated business processes where services are wired together into business flows and are often orchestrated using open standards such as BPEL. For example, consider an auto loan service, where a bank customer submits an application online. The service processes the application and does a credit check on the applicant. If the applicant's credit meets a certain standard, it's forwarded to the fulfillment service. After the processing is finished, the paperwork is sent to the orchestrating process (see Figure 4).

SOA is quite flexible and powerful, but its decoupled design makes it difficult to propagate an identity across business processes. For example, a transaction may span a multitude of messaging services such as Web Services, MQSeries, and JMS.

Each service has its own way of transporting identities. JMS and MQSeries can pass SOAP-based XML messages in their payload, but these services often aren't XML-based and use different payload types. SOAP-based Web Services have a distinct advantage over other messaging protocols since they can use WS-Security headers in the SOAP envelope to propagate identities (see Figure 5).

The WS-Security header is standardized security metadata located in a SOAP header in the SOAP envelope. WS-Security provides data integrity (XML encryption) and data authenticity (XML signature). In addition, it offers a way to insert standard security tokens such as X.509 certificates, Kerberos tickets, and Security Assertion Markup Language (SAML) assertions in the WS-Security header. For example, SAML was designed to provide a standardized exchange of security information using XML documents referred to as SAML assertions. The following code shows how an identity would be bound to a SOAP message using SAML:

<wsse:Security ...>
    . . .
    <saml:assertion= ...>
      . . .
      <saml:Subject>
        <saml:NameIdentifier ...>
          CN=Joe User, OU=purchasing, O=Widget Inc
        </saml:NameIdentifier>
      </saml:Subject>
    . . .
<wsse:Security ...>

Binding the original requestor's identity to the request itself is the way to propagate identities. The request may be modified throughout the lifecycle of the transaction, but the identity of the requester must always be attached to the request. In this context, identity propagation presents many advantages. At each step, the user's identity is used to determine access to any secured resource.

WS-Security provides the semantics for binding user information to SOAP messages. In the listing above, the identity of the user is Joe User, who is in the purchasing organization at Widget, Inc. This identity is bound to the SOAP message using SAML as defined by the open WS-Security.

The SAML token goes beyond just identifying the user. It can also package additional information about the user in the form of attributes, which are used for authorization decisions. Attribute statements provide specific details about the subject; for example, the user holds Gold status. Authorization decision statements identify what the subject is entitled to do. For example, SAML assertion attributes can be mapped to roles defined in an access control infrastructure. A relying party that processes a SAML token could use these statements for fine-grained access control.

SOA Identity Propagation
Let's return to the orchestrated business process example that accessed the credit rating and loan processing services. The fulfillment service could be exposed as a Web Service, but the credit rating service might use MQSeries to access a legacy database. These two services can use different means to propagate identities. If you need to tie these services together, how do you propagate the identity from SOAP into a native MQSeries? This can be the start of many headaches. If a business process spans multiple services, how do you relay the identity of the original requestor throughout the transaction?

To simplify this problem, identity propagation should ideally be carried out with a single security token - for instance, a SAML assertion as described above. Secure identity propagation lets you make sure that only appropriate requests are processed. It also provides an audit trail throughout a transaction. Identity propagation requires that the identity of the original requester be bound to each step of the business process or transaction.

Business processes found in SOAs often span a multitude of protocols. The security token should have a standard way to bind to these protocols. A SAML token, as a standard XML representation for describing user identity and attributes, is uniquely suited for this purpose. Figure 6 shows a simple example of a SAML token spanning the services and protocols in the credit check service.

Currently, a SAML token is attached only to SOAP protocols. It would be useful to extend it to other native protocols such as JMS, SQL*net/ODBC, or even Inter-ORB. Ideally, all SOA-protected resources should be able to leverage SAML tokens. These protected resources should also be able to use an identity management Single Sign-On (SSO) server to determine access rights based on the tokens. When a policy is changed in the SSO server, it would affect all of the components that use it for security decisions.


More Stories By Marc Chanliau

Marc Chanliau has been in the software industry for more than 20 years and is currently a director of product management at Oracle where he is responsible for Identity Management solutions and innovations. He is heavily involved in security and XML standards groups including serving as the first chair person of the OASIS Security Services Technical Committee (SSTC), which culminated in the adoption of SAML as an official OASIS standard, participating on the WS-Security Technical Committee, helping to define the Liberty Alliance 2.0 specifications, and participating in the Java Specification Request (JSR) committee.

More Stories By William Bathurst

William Bathurst is a senior product manager at Oracle with 18 years of industry experience. He is currently the product manager for J2EE security and web services management.

More Stories By Ramana Turlapati

Ramana Turlapati is a consulting member of the technical staff at Oracle with 12 years of industry experience. In his current role as the security architect for Oracle Web Services Manager, he contributes to Oracle's overall Web Services security strategies and solutions.

Comments (0)

Share your thoughts on this story.

Add your comment
You must be signed in to add a comment. Sign-in | Register

In accordance with our Comment Policy, we encourage comments that are on topic, relevant and to-the-point. We will remove comments that include profanity, personal attacks, racial slurs, threats of violence, or other inappropriate material that violates our Terms and Conditions, and will block users who make repeated violations. We ask all readers to expect diversity of opinion and to treat one another with dignity and respect.


@MicroservicesExpo Stories
It has never been a better time to be a developer! Thanks to cloud computing, deploying our applications is much easier than it used to be. How we deploy our apps continues to evolve thanks to cloud hosting, Platform-as-a-Service (PaaS), and now Function-as-a-Service. FaaS is the concept of serverless computing via serverless architectures. Software developers can leverage this to deploy an individual "function", action, or piece of business logic. They are expected to start within milliseconds...
As DevOps methodologies expand their reach across the enterprise, organizations face the daunting challenge of adapting related cloud strategies to ensure optimal alignment, from managing complexity to ensuring proper governance. How can culture, automation, legacy apps and even budget be reexamined to enable this ongoing shift within the modern software factory? In her Day 2 Keynote at @DevOpsSummit at 21st Cloud Expo, Aruna Ravichandran, VP, DevOps Solutions Marketing, CA Technologies, was jo...
The nature of test environments is inherently temporary—you set up an environment, run through an automated test suite, and then tear down the environment. If you can reduce the cycle time for this process down to hours or minutes, then you may be able to cut your test environment budgets considerably. The impact of cloud adoption on test environments is a valuable advancement in both cost savings and agility. The on-demand model takes advantage of public cloud APIs requiring only payment for t...
You know you need the cloud, but you’re hesitant to simply dump everything at Amazon since you know that not all workloads are suitable for cloud. You know that you want the kind of ease of use and scalability that you get with public cloud, but your applications are architected in a way that makes the public cloud a non-starter. You’re looking at private cloud solutions based on hyperconverged infrastructure, but you’re concerned with the limits inherent in those technologies.
Is advanced scheduling in Kubernetes achievable?Yes, however, how do you properly accommodate every real-life scenario that a Kubernetes user might encounter? How do you leverage advanced scheduling techniques to shape and describe each scenario in easy-to-use rules and configurations? In his session at @DevOpsSummit at 21st Cloud Expo, Oleg Chunikhin, CTO at Kublr, answered these questions and demonstrated techniques for implementing advanced scheduling. For example, using spot instances and co...
The cloud era has reached the stage where it is no longer a question of whether a company should migrate, but when. Enterprises have embraced the outsourcing of where their various applications are stored and who manages them, saving significant investment along the way. Plus, the cloud has become a defining competitive edge. Companies that fail to successfully adapt risk failure. The media, of course, continues to extol the virtues of the cloud, including how easy it is to get there. Migrating...
For DevOps teams, the concepts behind service-oriented architecture (SOA) are nothing new. A style of software design initially made popular in the 1990s, SOA was an alternative to a monolithic application; essentially a collection of coarse-grained components that communicated with each other. Communication would involve either simple data passing or two or more services coordinating some activity. SOA served as a valid approach to solving many architectural problems faced by businesses, as app...
Some journey to cloud on a mission, others, a deadline. Change management is useful when migrating to public, private or hybrid cloud environments in either case. For most, stakeholder engagement peaks during the planning and post migration phases of a project. Legacy engagements are fairly direct: projects follow a linear progression of activities (the “waterfall” approach) – change managers and application coders work from the same functional and technical requirements. Enablement and develo...
Gone are the days when application development was the daunting task of the highly skilled developers backed with strong IT skills, low code application development has democratized app development and empowered a new generation of citizen developers. There was a time when app development was in the domain of people with complex coding and technical skills. We called these people by various names like programmers, coders, techies, and they usually worked in a world oblivious of the everyday pri...
While some developers care passionately about how data centers and clouds are architected, for most, it is only the end result that matters. To the majority of companies, technology exists to solve a business problem, and only delivers value when it is solving that problem. 2017 brings the mainstream adoption of containers for production workloads. In his session at 21st Cloud Expo, Ben McCormack, VP of Operations at Evernote, discussed how data centers of the future will be managed, how the p...
From manual human effort the world is slowly paving its way to a new space where most process are getting replaced with tools and systems to improve efficiency and bring down operational costs. Automation is the next big thing and low code platforms are fueling it in a significant way. The Automation era is here. We are in the fast pace of replacing manual human efforts with machines and processes. In the world of Information Technology too, we are linking disparate systems, softwares and tool...
DevOps is good for organizations. According to the soon to be released State of DevOps Report high-performing IT organizations are 2X more likely to exceed profitability, market share, and productivity goals. But how do they do it? How do they use DevOps to drive value and differentiate their companies? We recently sat down with Nicole Forsgren, CEO and Chief Scientist at DORA (DevOps Research and Assessment) and lead investigator for the State of DevOps Report, to discuss the role of measure...
DevOps is under attack because developers don’t want to mess with infrastructure. They will happily own their code into production, but want to use platforms instead of raw automation. That’s changing the landscape that we understand as DevOps with both architecture concepts (CloudNative) and process redefinition (SRE). Rob Hirschfeld’s recent work in Kubernetes operations has led to the conclusion that containers and related platforms have changed the way we should be thinking about DevOps and...
"As we've gone out into the public cloud we've seen that over time we may have lost a few things - we've lost control, we've given up cost to a certain extent, and then security, flexibility," explained Steve Conner, VP of Sales at Cloudistics,in this SYS-CON.tv interview at 20th Cloud Expo, held June 6-8, 2017, at the Javits Center in New York City, NY.
These days, APIs have become an integral part of the digital transformation journey for all enterprises. Every digital innovation story is connected to APIs . But have you ever pondered over to know what are the source of these APIs? Let me explain - APIs sources can be varied, internal or external, solving different purposes, but mostly categorized into the following two categories. Data lakes is a term used to represent disconnected but relevant data that are used by various business units wit...
With continuous delivery (CD) almost always in the spotlight, continuous integration (CI) is often left out in the cold. Indeed, it's been in use for so long and so widely, we often take the model for granted. So what is CI and how can you make the most of it? This blog is intended to answer those questions. Before we step into examining CI, we need to look back. Software developers often work in small teams and modularity, and need to integrate their changes with the rest of the project code b...
"I focus on what we are calling CAST Highlight, which is our SaaS application portfolio analysis tool. It is an extremely lightweight tool that can integrate with pretty much any build process right now," explained Andrew Siegmund, Application Migration Specialist for CAST, in this SYS-CON.tv interview at 21st Cloud Expo, held Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA.
"Cloud4U builds software services that help people build DevOps platforms for cloud-based software and using our platform people can draw a picture of the system, network, software," explained Kihyeon Kim, CEO and Head of R&D at Cloud4U, in this SYS-CON.tv interview at 21st Cloud Expo, held Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA.
Kubernetes is an open source system for automating deployment, scaling, and management of containerized applications. Kubernetes was originally built by Google, leveraging years of experience with managing container workloads, and is now a Cloud Native Compute Foundation (CNCF) project. Kubernetes has been widely adopted by the community, supported on all major public and private cloud providers, and is gaining rapid adoption in enterprises. However, Kubernetes may seem intimidating and complex ...
DevOps is often described as a combination of technology and culture. Without both, DevOps isn't complete. However, applying the culture to outdated technology is a recipe for disaster; as response times grow and connections between teams are delayed by technology, the culture will die. A Nutanix Enterprise Cloud has many benefits that provide the needed base for a true DevOps paradigm. In their Day 3 Keynote at 20th Cloud Expo, Chris Brown, a Solutions Marketing Manager at Nutanix, and Mark Lav...