Natural or man-made crises and disasters often bring large scale financial, environmental and human losses and can result in widespread damage to the information infrastructure. This affects the responding agencies’ ability to communicate, with restrictions on the sharing of information making it difficult for them to provide emergency services to the population. Emergency ad hoc communication networks and systems can be established for use by the responding agencies, but these need to maintain an acceptable level of security. This paper discusses how to intelligently construct such an ad hoc network from existing assured systems, and how to ensure that the resultant composite system, or System-of-Systems (SOS), achieves a satisfactory level of information assurance. The paper also highlights possible threats and vulnerabilities to information and recommends possible solutions using SOS Security during crisis response to ensure that all organisations can securely and efficiently perform operational tasks during a crisis.