IT Ecosystems - Part III

Here is part III of my discussion piece on IT ecosystems. This post covers system decomposition and reuse with SOA, and the associated security issues that companies may face in implementing such strategies.

3. Decomposition is all the rage with enterprise systems- we could for instance use the ecommerce system's web services layer and the SOA/ESB to decompose the system into its individual processes, then expose those processes as needed across the enterprise. Again, I wonder where the useful limits of that metaphor are. One idea is to provide a common header in the content management system that contains an AJAX component to expose the customer shopping cart on any external-facing web property in our infrastructure. Nifty idea in principle, but it raises some serious questions about security.

Dave Watts:

…issues with session hijacking, etc, are no
different for exposed services than for any other web applications.
Typically, in my experience, a big part of making SOA happen is wrapped in
authentication/authorization services. On the other hand, the more exposed
something is, the more likely you will discover problems with it.

Rob Brooks-Bilson:

I think this is where process mapping comes in.  If you first define the business processes you are interested in, you can then map those process across system boundaries.  This can be fairly simple to do, or a royal PITA depending on how mature your business is, and how well defined existing business processes are.

Security is an issue here (especially for externally exposed services).  It's not overly difficult to do, but there are a lot of options depending on what type of services you expose (web servivces, RPC, gateways, etc.).

Security is becoming a bigger and bigger component of IT efforts in companies from startups to multi-national conglomerates. SOA strategies create two serious issues for enterprise IT. By decomposing applications into their component processes and exposing them to other applications via SOA, IT may create a situation where applications are both dependent on one another and are linked across a common platform.  

The dependencies create a scenario where applications could be subjected to outages because other applications on which they depend are compromised. Critical business functions like invoicing need to be fault-tolerant and hardened against indirect attacks. Second, linking applications across a common platform creates a situation where an attacker needs only to find one good attack vector into the SOA itself in order to potentially compromise many systems.