On Friday afternoon, 21 October, several major websites including Twitter and Spotify became unreachable or painfully slow. The mystery cleared when reports pointed to DDoS attacks aimed at DNS provider Dyn.
What is Dyn?
Dyn is a DNS company that many websites rely on. When you type an address in your browser, DNS acts like a switchboard that finds the right servers. When a large provider like Dyn is overwhelmed, its customers go dark too.
What is a DDoS?
Distributed denial-of-service attacks flood a site or service from many sources at once so legitimate requests cannot get through. Ordinary users trying to load a page become part of the pile-up.
Why did it happen?
Who launched the attack, and why, is still unknown. It looks like a continuation of escalating probes against sites and providers in recent weeks, possibly testing defenses. Friday’s waves were the largest yet.
Because the United States felt the brunt, some observers floated state or terror motives. While Dyn was impaired, affected sites lost potential revenue; early chatter put economic damage in the billions. Cyberattacks can rival physical strikes in cost. If harming the U.S. online economy was the goal, the attackers scored a temporary win.
Sites hit included Twitter, Spotify, Shopify, Box, Etsy, GitHub, HBO Now, Airbnb, Yelp, Pinterest, Starbucks, and many others, plus outlets such as Wired, Reddit, The Verge, and Business Insider.
How it unfolded
Traffic in the U.S. briefly stalled until Dyn mitigated the first wave. Attackers came back harder with a second assault, then a third after that was contained.
Operators likely used an Internet of Things botnet: cheap, poorly secured connected devices infected with malware. Any internet-linked gadget can join a DDoS swarm. If you have ever installed shady files on a PC or smart device, you might have been an unwitting node.
Switching DNS resolvers can sometimes reduce the blast radius. In Turkey, people already use alternate DNS to work around censorship, which may have softened the local impact.
Dyn was not alone in responding: the White House said work had begun to identify those responsible.
Source: TechCrunch
