Memcached is an open source utility designed to cache in RAM frequently used web pages. Some Linux instances by default have left TCP or UDP port 11211 open to internet-borne requests. The utility was never designed to be internet-accessible and requires no authentication to access. One of its customers, a U.S.-based service provider, was hit by a 1.7 Tbps reflection/amplification attack on the same server. DDoS extortionists are now threatening to unleash DDoS disruptions on victims unless they pay ransoms of 50 monero – aka XMR – cryptocurrency.”]
Source: https://www.careersinfosecurity.com/memcached-ddos-attacks-95000-servers-vulnerable-to-abuse-a-10705