Follow @Openwall on Twitter for new release announcements and other news
[<prev] [next>] [thread-next>] [day] [month] [year] [list]
Date: Fri, 2 Mar 2018 12:44:28 +0100
From: Hanno Böck <>
Subject: memcached UDP amplification attacks


In the past days there have been reports about some DDoS attacks
abusing the memcached UDP protocol:

The issue: memcached has an UDP protocol that allows getting a much
larger reply than the query sent, thus allowing amplification attacks
with forged sender IPs.

Upstream memcached reacted by disabling the UDP-based protocol by
This is good, however one could argue that they should also default to
localhost only.

Most distros I checked right now default to enabling UDP, but
restricting connections to While this is not directly
vulnerable it's only a minor change away from being so. The memcached
announcement sounds like the UDP protocol is rarely used and should be
considered deprecated and replaced by the TCP-based one.

I recommend all distributions consider changing their defaults to
disabling the UDP-based memcached protocol by default.

Hanno Böck

GPG: FE73757FA60E4E21B937579FA5880072BBB51E42

Powered by blists - more mailing lists

Please check out the Open Source Software Security Wiki, which is counterpart to this mailing list.

Confused about mailing lists and their use? Read about mailing lists on Wikipedia and check out these guidelines on proper formatting of your messages.