ADEPTS: adaptive intrusion response using attack graphs in an E-commerce environment. Distributed systems with multiple interacting services, especially e-commerce systems, are suitable targets for malicious attacks because of the potential financial impact. Compared to intrusion detection, automated response has received relatively less attention. In this paper, we present the design of automated response mechanisms in an intrusion tolerant system called ADEPTS. Our focus is on enforcing containment in the system, thus localizing the intrusion and allowing the system to provide service, albeit degraded. ADEPTS uses a graph of intrusion goals, called I-GRAPH, as the underlying representation in the system. In response to alerts from an intrusion detection framework, ADEPTS executes algorithms to determine the spread of the intrusion and the appropriate responses to deploy. A feedback mechanism evaluates the success of a deployed response and uses that in guiding future choices. ADEPTS is demonstrated on a distributed e-commerce system and evaluated using a survivability metric.