How do distributed denial-of-service attacks shut down websites?

A distributed denial-of-service (DDoS) attack is a form of cybercrime that renders a website unavailable by overwhelming its servers with a flood of traffic, preventing legitimate users from accessing the site.12

The process typically involves the following steps:

• Infection: A criminal compromises a large number of devices—such as computers, baby monitors, or digital cameras—by installing Trojan horses. These programs often arrive disguised as benign files, like email attachments, and remain hidden until triggered.12
• Botnet Formation: The collection of these infected, internet-connected devices is known as a botnet.1
• Execution: At a predesignated time, the attacker triggers the botnet to send a massive volume of requests to a specific target site simultaneously.12

By forcing the target's servers to process this deluge of artificial traffic, the site becomes so tied up that it cannot respond to requests from real users, effectively shutting it down. This highlights the critical importance of maintaining secure software and implementing regular updates to prevent devices from being co-opted into such malicious networks.12