New Active Exploit: memcached on port 11211 UDP & TCP being exploited for reflection attacks

Job Snijders job at ntt.net
Thu Mar 1 01:52:48 UTC 2018


On Tue, Feb 27, 2018 at 09:52:54PM +0000, Chip Marshall wrote:
> On 2018-02-27, Ca By <cb.list6 at gmail.com> sent:
> > Please do take a look at the cloudflare blog specifically as they
> > name and shame OVH and Digital Ocean for being the primary sources
> > of mega crap traffic
> > 
> > https://blog.cloudflare.com/memcrashed-major-amplification-attacks-from-port-11211/
> > 
> > Also, policer all UDP all the time... UDP is unsafe at any speed.
> 
> Hi, DigitalOcean here. We've taken steps to mitigate this attack on
> our network.

NTT too has deployed rate limiters on all external facing interfaces on
the GIN backbone - for UDP/11211 traffic - to dampen the negative impact
of open memcached instances on peers and customers. 

The toxic combination of 'one spoofed packet can yield multiple reponse
packets' and 'one small packet can yield a very big response' makes the
memcached UDP protocol a fine example of double trouble with potential
for severe operational impact.

Kind regards,

Job


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