Some 300,000 IPs vulnerable to this Loop DoS attack

As many as 300,000 servers or devices on the public internet are thought to be vulnerable right now to the recently disclosed Loop Denial-of-Service technique that works against some UDP-based application-level services. It's said that certain implementations of TFTP, DNS, and NTP, as well as legacy protocols, such as Echo, Chargen, and QOTD, are at risk. Exploitation may result in services going down, if not whole machines or networks. Judging from DNS, NTP, and TFTP scans, the largest number of public-facing potentially vulnerable systems are in China, Russia, and America, followed by Iran, South Korea, Italy, France, Canada, and Brazil. The method of attack was disclosed earlier this week by researchers Christian Rossow and Yepeng (Eric) Pan at the CISPA Helmholtz Center for Information Security in Germany. It's pretty trivial, and basically relies on sending an error message to, let's say, vulnerable server A in such a way, using IP address source spoofing, that server A responds with an error message to vulnerable server B, which sends an error message to A, which responds to B, which responds to A, over and over again in an infinite loop. All you have to do is fire off enough messages at server A so that the ensuing storm of UDP packets between A and B consumes the machines' resources and causes them to stop responding to legit requests. For all normal users, the servers will appear to be unavailable. "For example, imagine two services that respond with an error message...