A new type of denial of service attack has emerged, with an impact right across the internet, security experts have warned.
The new style distributed denial of service attack hits target organisations by flooding their e-mail systems with queries bounced off domain name system (DNS) servers. The attacks involve a malicious attacker sending several thousand spoofed requests to a DNS server.
Traditional DOS attacks use networks of compromised servers to directly attack an organisation.
DNS servers that are configured to provide “recursion” receive the fake requests and in turn generate thousands of replies to the targeted victim. The target can receive so many inbound DNS replies to the spoofed query that all available bandwidth resources are used up.
The US Computer Emergency Readiness Team has warned that such attacks have an impact across the internet, hitting the DNS servers themselves, the root name servers that are part of the internet’s critical infrastructure, internet service providers and the individual intended target.
Security firm VeriSign has traced around 1,500 attacks over just a few weeks at the start of this year. It said some attacks had generated up to eight gbps of spurious data.