Date: Fri, 2 Mar 2018 04:58:50 -0700 From: Kurt Seifried <kseifried@...hat.com> To: oss-security <oss-security@...ts.openwall.com> Subject: Re: memcached UDP amplification attacks On Fri, Mar 2, 2018 at 4:44 AM, Hanno Böck <hanno@...eck.de> wrote: > Hi, > > In the past days there have been reports about some DDoS attacks > abusing the memcached UDP protocol: > https://blog.cloudflare.com/memcrashed-major-amplification-attacks-from- > port-11211/ > https://www.wired.com/story/github-ddos-memcached/ > > > 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 > default: > https://github.com/memcached/memcached/wiki/ReleaseNotes156 > 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 127.0.0.1. 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. > > I think in general ALL network applications that support UDP need to think about hardening their default configurations due to the potential for amplification attacks. While it is not yet CVE worthy I can see the bar moving (much like it has for default passwords, and crypto) in the near future as this is clearly becoming a problem. Please note that this problem is already covered by CWE-406 (to some degree) which makes the case for CVE assignment stronger. > -- > Hanno Böck > https://hboeck.de/ > > mail/jabber: hanno@...eck.de > GPG: FE73757FA60E4E21B937579FA5880072BBB51E42 > -- Kurt Seifried -- Red Hat -- Product Security -- Cloud PGP A90B F995 7350 148F 66BF 7554 160D 4553 5E26 7993 Red Hat Product Security contact: secalert@...hat.com
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.