<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><meta http-equiv="Content-Type" content="text/html charset=utf-8" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div class=""><p style="box-sizing: inherit; border: 0px; font-family: Lato, sans-serif; font-size: 15px; margin: 0px 0px 1.5em; outline: 0px; padding: 0px; vertical-align: baseline; color: rgb(88, 88, 90); font-variant-ligatures: normal; orphans: 2; widows: 2; background-color: rgb(255, 255, 255);" class=""><strong style="box-sizing: inherit; border: 0px; font-family: inherit; font-style: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;" class="">UPDATE: As of 2018-02-28, more attacks using the </strong>memcached<strong style="box-sizing: inherit; border: 0px; font-family: inherit; font-style: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;" class=""> reflection vector have been unleashed on the Internet. Operators are asked to port filter (Exploitable Port Filters), rate </strong>limits<strong style="box-sizing: inherit; border: 0px; font-family: inherit; font-style: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;" class=""> the port 11211 UDP traffic (ingress and egress), and clean up any </strong>memcached<strong style="box-sizing: inherit; border: 0px; font-family: inherit; font-style: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;" class=""> exposed to the Internet (</strong>iptables<strong style="box-sizing: inherit; border: 0px; font-family: inherit; font-style: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;" class=""> on UNIX works). These mitigations should be on IPv4 and IPv6! There is not excuse for ISPs, Telcos, and other operators for not acting. NTT is an example of action. As stated by Job Snijders <<a href="mailto:job@ntt.net" class="">job@ntt.net</a>> on the NANOG List:</strong></p><blockquote style="box-sizing: inherit; border: 0px; font-family: Lato, sans-serif; font-size: 15px; margin: 0px 1.5em 0px 0px; outline: 0px; padding: 0px 0px 0px 3.5em; vertical-align: baseline; quotes: '' ''; background-image: url(applewebdata://34C49381-1647-44BC-8C02-43CACDFCC6B7/library/images/quote.png); background-color: rgb(255, 255, 255); color: rgb(88, 88, 90); font-variant-ligatures: normal; orphans: 2; widows: 2; background-position: left top; background-repeat: no-repeat no-repeat;" class=""><p style="box-sizing: inherit; border: 0px; font-family: inherit; font-style: inherit; margin: 0px 0px 1.5em; outline: 0px; padding: 0px; vertical-align: baseline;" class=""><strong style="box-sizing: inherit; border: 0px; font-family: inherit; font-style: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;" class="">“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.</strong></p><p style="box-sizing: inherit; border: 0px; font-family: inherit; font-style: inherit; margin: 0px 0px 1.5em; outline: 0px; padding: 0px; vertical-align: baseline;" class=""><strong style="box-sizing: inherit; border: 0px; font-family: inherit; font-style: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;" class="">The toxic combination of ‘one spoofed packet can yield multiple reponse packets’ and ‘one small packet can yield a very big response’ makes the</strong><br style="box-sizing: inherit;" class=""><strong style="box-sizing: inherit; border: 0px; font-family: inherit; font-style: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;" class="">memcached UDP protocol a fine example of double trouble with potential for severe operational impact.”</strong></p></blockquote></div><div class="">This post has been updated with recommendations. Check with your network vendors for deployment/configuration details.</div><div class=""><br class=""></div><div class=""><a href="http://www.senki.org/memcached-on-port-11211-udp-tcp-being-exploited/" class="">http://www.senki.org/memcached-on-port-11211-udp-tcp-being-exploited/</a></div><div class=""><br class=""></div><div class=""><br class=""></div><div class=""><br class=""></div><br class=""><div class=""><blockquote type="cite" class=""><div class="">On Feb 27, 2018, at 3:20 PM, Barry Greene <<a href="mailto:bgreene@senki.org" class="">bgreene@senki.org</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div class="">Hello Fellow MENOG Colleagues,<br class=""><br class="">We (various Operator Security Community) are working to head off another reflection DOS vector.<br class=""><br class="">All Operators and Enterprise Networks – memcached on port 11211 UDP & TCP being exploited. This is now new. We know how reflection attacks work (send a spoofed packet to a device and have it reflected back (see illustration).<br class=""><br class="">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. This white paper provides details on Exploitable Port Filters: <a href="http://www.senki.org/operators-security-toolkit/filtering-exploitable-ports-and-minimizing-risk-to-and-from-your-customers/" class="">http://www.senki.org/operators-security-toolkit/filtering-exploitable-ports-and-minimizing-risk-to-and-from-your-customers/</a><br class=""><br class="">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.<br class=""><br class="">Deploying these filters will help protect your network, your organization, your customers, and the Internet.<br class=""><br class="">Ping me 1:1 if you have questions.<br class=""><br class="">Sincerely,<br class=""><br class="">--<br class="">Barry Raveendran Greene<br class="">Security Geek helping with OPSEC Trust<br class="">Mobile: +1 408 218 4669<br class="">E-mail: <a href="mailto:bgreene@senki.org" class="">bgreene@senki.org</a><br class=""><br class="">----------------------------<br class="">Resources on memcached Exploit (to evaluate your risk):<br class=""><br class="">More information about this attack vector can be found at the following:<br class=""><br class=""><span class="Apple-tab-span" style="white-space:pre"> </span>• JPCERT – memcached のアクセス制御に関する注意喚起 (JPCERT-AT-2018-0009)<br class=""><a href="http://www.jpcert.or.jp/at/2018/at180009.html" class="">http://www.jpcert.or.jp/at/2018/at180009.html</a><br class=""><span class="Apple-tab-span" style="white-space:pre"> </span>• Qrator Labs: The memcached amplification attacks reaching 500 Gbps<br class=""><a href="https://medium.com/@qratorlabs/the-memcached-amplification-attack-reaching-500-gbps-b439a7b83c98" class="">https://medium.com/@qratorlabs/the-memcached-amplification-attack-reaching-500-gbps-b439a7b83c98</a><br class=""><span class="Apple-tab-span" style="white-space:pre"> </span>• Arbor Networks: memcached Reflection/Amplification Description and DDoS Attack Mitigation Recommendations<br class="">https://www.arbornetworks.com/blog/asert/memcached-reflection-amplification-description-ddos-attack-mitigation-recommendations/<br class=""><span class="Apple-tab-span" style="white-space:pre"> </span>• Cloudflare: Memcrashed – Major amplification attacks from UDP port 11211<br class="">https://blog.cloudflare.com/memcrashed-major-amplification-attacks-from-port-11211/<br class=""><span class="Apple-tab-span" style="white-space:pre"> </span>• Link11: New High-Volume Vector: Memcached Reflection Amplification Attacks<br class="">https://www.link11.com/en/blog/new-high-volume-vector-memcached-reflection-amplification-attacks/<br class=""><span class="Apple-tab-span" style="white-space:pre"> </span>• Blackhat Talk: The New Page of Injections Book: Memcached Injections by Ivan Novikov<br class="">https://www.blackhat.com/docs/us-14/materials/us-14-Novikov-The-New-Page-Of-Injections-Book-Memcached-Injections-WP.pdf<br class=""><span class="Apple-tab-span" style="white-space:pre"> </span>• Memcache Exploit<br class="">http://niiconsulting.com/checkmate/2013/05/memcache-exploit/<br class=""></div></div></blockquote></div><br class=""></div></body></html>