On October 21st last week, the internet suffered a massive DNS attack. It was touch and go for a few hours, but the web pulled through.
For many, though, it’s not clear exactly what happened, or what it means in terms of security. So let’s take a little look.
On the 21st, you may have noticed that services and sites like Twitter, Spotify and GitHub were either slow or offline completely. This is because there was a large-scale attack against DNS (Domain Name System) services. A DNS attack affects the very framework of the web, and means that websites become near unusable.
The Domain Name System is a sort of online address book that allows us to surf the web using site names and URLs instead of the IP addresses that denote the server on which the website lives; the physical location of the website, if you will. When you type in “surfeasy.com” to your browser, DNS takes this address and immediately finds the website’s IP address, then sends to you that address. The DNS means that you don’t have to type in IP addresses when you want to visit a website, and it works fantastically.
When DNS services are attacked, though, this process slows or stops altogether, and websites become slow or inaccessible to most users.
There are many companies that provide DNS services, and each one corresponds to thousands of websites. When they are attacked, the attackers bombard the provider with a massive amounts of requests in order to overload the system so legitimate traffic cannot access the service. Imagine everyone in a country calling into one pizza delivery place all at once. No one would end up with a pizza.
On the 21st, the DNS provider DynDNS was attacked three times throughout the day. The attack involved tens of millions of IP addresses, and attackers used the Mirai software, which allows users to “weaponize” networks of thousands or even millions of net-connected devices to launch these attacks. Each of the three attacks on the 21st was resolved within hours, but for those few hours, a whole load of websites were on their knees.
With the growing number of devices connected to the net, it’s likely that such attacks will be more frequent—and that the web will suffer because of them.
This latest attack, and the several large-scale hacks of the last couple of years, go to prove one thing: Security threats are everywhere. Investing in your online security is no longer just a good idea; it’s essential.