https://arstechnica.com/information-technology/2019/09/in-the-wild-ddoses-are-abusing-webcams-and-dvrs-to-amplify-their-crippling-effects/

Hackers have found a new way to amplify the crippling effects of denial-of-service technique by abusing an improperly implemented tool found in almost 1 million network-connected cameras, DVRs, and other Internet-of-things devices.

The technique abuses WS-Discovery, a protocol that a wide array of network devices use to automatically connect to one another. Often abbreviated as WSD, the protocol lets devices send user datagram protocol packets over port 3702 that describe the device capabilities and requirements. Devices that receive the probes can respond with replies that can be tens to hundreds of times bigger. WSD has shipped with Windows since Vista and is one of the ways the operating system automatically finds network-based printers.