Service Oriented Architecture (SOA) is making it possible to build business applications by assembling parts of other applications. The development process is fast and thus if an organization chooses to build the right business applications, the benefits come quickly. SOA is about threading multiple applications together, but only using the functionality you need. To achieve this, SOA abstracts the business functionality of specific applications allowing them to be discovered and used by other applications. This presents an IT security problem. Users will most likley have different privileges for different applications, and thus they will need to be authenticated.”]
Source: https://www.csoonline.com/article/2119144/it-security-and-soa.html