Distributed denial-of-service attacks target websites and online services. The aim is to overwhelm them with more traffic than the server or network can accommodate. The goal is to render the website or service inoperable.

The traffic can consist of incoming messages, requests for connections, or fake packets. In some cases, the targeted victims are threatened with a DDoS attack or attacked at a low level. This may be combined with an extortion threat of a more devastating attack unless the company pays a cryptocurrency ransom. In 2015 and 2016, a criminal group called the Armada Collective repeatedly extorted banks, web host providers, and others in this way.

DDoS attacks are sometimes done to divert the attention of the target organization. While the target organization focuses on the DDoS attack, the cybercriminal may pursue a primary motivation such as installing malicious software or stealing data.

DDoS attacks have been used as a weapon of choice of hacktivists, profit-motivated cybercriminals, nation states and even — particularly in the early years of DDoS attacks — computer whizzes seeking to make a grand gesture.

Examples of DDoS attacks

Here’s a bit of history and two notable attacks.

In 2000, Michael Calce, a 15-year-old boy who used the online name “Mafiaboy,” launched one of the first recorded DDoS attacks. Calce hacked into the computer networks of a number of universities. He used their servers to operate a DDoS attack that crashed several major websites, including CNN, E-Trade, eBay, and Yahoo. Calce was convicted of his crimes in the Montreal Youth Court. As an adult, he became a “white-hat hacker” identifying vulnerabilities in the computer systems of major companies.

More recently, in 2016, Dyn, a major domain name system provider — or DNS — was hit with a massive DDoS attack that took down major websites and services, including AirBnB, CNN, Netflix, PayPal, Spotify, Visa, Amazon, The New York Times, Reddit, and GitHub.

The gaming industry has also been a target of DDoS attacks, along with software and media companies.