Memcached

memcached (1.4.25-2ubuntu1.3) xenial-security; urgency=medium

 * memcached is now configured to disable its UDP port by default, to
   prevent its use as a DDoS amplifier. To re-enable UDP service, add
   '-U 11211' to /etc/memcached.conf and restart the memcahced service.
-- Steve Beattie <sbeattie@ubuntu.com>  Mon, 05 Mar 2018 01:11:43 -0800

• https://blog.cloudflare.com/memcrashed-major-amplification-attacks-from-port-11211/
• https://github.com/memcached/memcached/wiki/ConfiguringServer