Enterprise networks are constantly under attack by adversaries capable of evading existing host and network based security applications. Current defensive technologies utilize persistent defensive agents on each network system or workstation. The continued proliferation of attacks suggests that current agent-based approaches to enterprise resiliency have limited effectiveness in protecting systems from compromise. To provide resilient enterprise network defense, new techniques must be developed that support enterprise network resiliency, fight-through, and survivability. To address these issues, IAI will develop Virtual Shield, a virtualization-based framework, to protect systems in an enterprise network. Virtual Shield adopts various resilient techniques to make the protection approaches more agile and adaptive to cyber attacks. The system also employs a virtual machine introspection technique to monitor the execution of an end system and detect malware without deploying agents in the monitored system. Moreover, Virtual Shield fully utilizes virtualization to implement the capabilities of freezing, duplicating, and moving an end system in the network, thus making moving target defense feasible.