ISECAP is an advanced packet filtering framework designed for use with the Internet Scale Event and Attack Generation Environment (ISEAGE) at Iowa State University. ISEAGE is a network security test bed where cyber attacks can be carried out for security research. ISECAP functions as a FreeBSD-based general purpose packet control system designed to alter ISEAGE network data as it is being transmitted. Scripts are interpreted by ISECAP to modify network data in real-time, assisting in the simulation and obfuscation of various network attacks tested at the ISEAGE facility. The ISECAP system is developed as a flexible tool with a forward focus on ease of extensibility to meet the future needs of ISEAGE.