This article is targeted on investigating the web-services dependability problem and, in particular, the reasonableness of multi version architecture usage to solve it and guarantee the customer he is safe while using the web-service. It provides a reader with general information about web-services architecture, challenges that such architecture faces and ways of solving such problems. The design of the model used for analysis of multi version architecture is represented. Results of comparison of different model configurations are carried out showing the vulnerabilities of each configuration. The efficiency of multi version service oriented architecture is proved on a basis of the experimental research. Key words: web-service, Service Oriented Architecture, SOA, dependability, vulnerability, intruders, multi-version, majority element, web server, application server, database management system (DBMS).
