msm1267 writes "While the big traffic numbers and the spat between Spamhaus and illicit webhost Cyberbunker are grabbing big headlines, the underlying and percolating issue at play here has to do with the open DNS resolvers being used to DDoS the spam-fighters from Switzerland. Open resolvers do not authenticate a packet-sender’s IP address before a DNS reply is sent back. Therefore, an attacker that is able to spoof a victim’s IP address can have a DNS request bombard the victim with a 100-to-1 ratio of traffic coming back to them versus what was requested. DNS amplification attacks such as these have been used lately by hacktivists, extortionists and blacklisted webhosts to great success."
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