Today computing systems employ high interaction between people and services. It is more than obvious that todays society depends every day more on such computing systems. Furthermore we cannot deny that consequences of their failures can have high cost, from financial resources loss to even human lives loss. Modern large scale distributed systems services must provide guarantees for protecting services against malicious threats. So security is becoming more important, as services can become victims of malicious attacks that can result in code injection that can affect critical components on a large scale. Because of such catastrophic consequences it has become mandatory for developers to provide security guarantees for users, usually in the form of protection mechanisms that can protect the system against the malicious behavior of services. In this paper we propose one such solution to provide security mechanisms and guarantees against security threats in large scale distributed environment. Such mechanisms consider the needs of modern distributed service-oriented applications. We propose security policies designed to handle security guarantees imposed by such applications. In the end, we present experimental results that reflect the capacity of the proposed security mechanisms and policies to correctly handle a wide range of security threats.