In IoTivity through 1.3.1 the CoAP server interface can be used for Distributed Denial of Service attacks using source IP address spoofing and UDP-based traffic amplification. The reflected traffic is 6 times bigger than spoofed requests. This occurs because the construction of a \4.01 Unauthorized\ response is mishandled. NOTE: the vendor states \While this is an interesting attack there is no plan for maintainer to fix as we are migrating to IoTivity Lite.\