The efforts and findings of the last decades of research on the formalization and the verification of Web services have given a certain level of assurance on Web services. However new challenges such as high availability and security issues are not fully addressed. In fact, Web services are exposed to attacks that appear continuously. These issues have naturally paved the way to a new research topic that aims at providing new techniques for making Web services attack tolerant. In this paper, we present a state of the art of attack tolerance, especially for Web services. We also present our approach to address such issues through a combination of techniques leveraging in particular diversification. The paper ends with our promising results and a discussion to highlight the perspectives and research direction