Web services enable the communication of application- to-application in a heterogeneous network and computing environment. The powerful functionality of Web services has given benefits to enterprise companies, such as rapid integrating between heterogeneous e-business systems, easy implementation of e-business systems, and reusability of e-business services. While providing the flexibility for e-business, Web services tend to be vulnerable to a number of attacks. Core components of Web services such as simple object access protocol (SOAP), Web services description language (WSDL), and universal description, discovery, and integration (UDDI) can be exploited by malicious attacks due to lack of proper security protections. These attacks will increase the risk of e-business that employs Web services. This chapter aims to provide a state-of-the-art view of Web services attacks and countermeasures. We examine various vulnerabilities in Web services and then followed by the analysis of respective attacking methods. We also discuss preventive countermeasures against such attacks to protect Web services deployments in e-business. Finally, we address future trends in this research area.