nanog mailing list archives

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


From: Ca By <cb.list6 () gmail com>
Date: Wed, 28 Feb 2018 00:41:43 +0000

On Tue, Feb 27, 2018 at 4:29 PM Filip Hruska <fhr () fhrnet eu> wrote:

This is just stupid.

OVH is one of the largest server providers in the world - of course they
will be at the top of that list.
What exactly should they do, according to you?


They should have rough norms enforced on their traffic behavior ,
especially around udp. If they do 1tbs of udp, they should police to 3tbs
or something similar.

Why should people de-peer them?


Abuse.  But abuse happens, failure to fix chronic is a reason to depeer...
not one off. Personally, i do not peer with ovh because i need my upstream
to rtbh their traffic.



Regards,
Filip Hruska

On 28 Feb 2018 at 1:13 am, <Dan Hollis <goemon () sasami anime net>> wrote:

OVH does not suprise me in the least.

Maybe this is finally what it will take to get people to de-peer them.

-Dan

On Tue, 27 Feb 2018, Ca By wrote:

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.


On Tue, Feb 27, 2018 at 12:28 PM Barry Greene  wrote:

Hello Fellow NANOGer,

If you have not already seen it, experiences it, or read about it, working
to head off another reflection DOS vector. This time it is memcached on
port 11211 UDP & TCP. There are active exploits using these ports.
Reflection attacks and the memcached is not new. We know how reflection
attacks work (send a spoofed packet to a device and have it reflected  back
(yes please deploy source address validation and BCP 38).

Operators are asked to review their networks and consider updating their
Exploitable Port Filters (Infrastructure ACLs) to track or block UDP/TCP
port 11211 for all ingress and egress traffic. If you do not know about
iACLs or Explorable port filters, you can use this white paper details and
examples from peers on Exploitable Port Filters:
http://www.senki.org/operators-security-toolkit/filtering-exploitable-ports-and-minimizing-risk-to-and-from-your-customers/


Enterprises are also asked to update their iACLs, Exploitable Port
Filters, and Firewalls to track or block UDP/TCP port 11211 for all ingress
and egress traffic.

Deploying these filters will help protect your network, your organization,
your customers, and the Internet.

Ping me 1:1 if you have questions.

Sincerely,

--
Barry Raveendran Greene
Security Geek helping with OPSEC Trust
Mobile: +1 408 218 4669
E-mail: bgreene () senki org

----------------------------
Resources on memcached Exploit (to evaluate your risk):

More information about this attack vector can be found at the following:

        • JPCERT – memcached のアクセス制御に関する注意喚起 (JPCERT-AT-2018-0009)
http://www.jpcert.or.jp/at/2018/at180009.html
        • Qrator Labs: The memcached amplification attacks reaching 500
Gbps

https://medium.com/@qratorlabs/the-memcached-amplification-attack-reaching-500-gbps-b439a7b83c98
        • Arbor Networks: memcached Reflection/Amplification Description
and DDoS Attack Mitigation Recommendations

https://www.arbornetworks.com/blog/asert/memcached-reflection-amplification-description-ddos-attack-mitigation-recommendations/
        • Cloudflare: Memcrashed – Major amplification attacks from UDP
port 11211

https://blog.cloudflare.com/memcrashed-major-amplification-attacks-from-port-11211/
        • Link11: New High-Volume Vector: Memcached Reflection
Amplification Attacks

https://www.link11.com/en/blog/new-high-volume-vector-memcached-reflection-amplification-attacks/
        • Blackhat Talk: The New Page of Injections Book: Memcached
Injections by Ivan Novikov

https://www.blackhat.com/docs/us-14/materials/us-14-Novikov-The-New-Page-Of-Injections-Book-Memcached-Injections-WP.pdf
        • Memcache Exploit
http://niiconsulting.com/checkmate/2013/05/memcache-exploit/







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