In the emerging world of embedded systems, as autonomous platforms (UAVs, SUAVs, etc) are being used for defense and aerospace, there is growing interest in advanced means to secure these systems and related information from menacing intruders. This article provides an overview of possible security threats for embedded systems utilized in defense/aerospace, and also covers available techniques for securing these systems and the information that they contain. The defense and aerospace sector is subject to a variety of security threats through all phases of the life cycle of an embedded system. This starts with cyber‐attacks to gain access to vendors’ servers and steal design information, continues with efforts to take control of the embedded systems or retrieve classified information from the aircraft, UAVs, SUAVs, etc. during their infield deployment, and, in case of crashed UAV or loss of control, extract critical information from or reverse‐engineer/clone different hardware and software elements of the system.