DDoS attack (distributed denial of service)

An attack that floods a website, server or network with so much traffic from many sources that it slows down or becomes unavailable to legitimate users.

In a distributed denial-of-service attack, the attacker usually uses a botnet of compromised devices to send overwhelming amounts of traffic at a target. Because the traffic comes from many locations at once, simply blocking one address does not stop it. Attacks may target a website, an online ordering system, a VPN gateway or an internet connection itself.

For most small businesses, DDoS is a lower risk than phishing or ransomware, but it can still matter. A business that depends on online bookings or e-commerce can lose sales during an outage, and DDoS is sometimes used as a distraction or alongside extortion demands. Hosting providers and content delivery networks often include basic protection that you may already be paying for.

Practical tip: ask your website host and internet provider what DDoS protection is included and how they respond to attacks. If your website is critical to revenue, consider placing it behind a content delivery network or web application firewall service that can absorb attack traffic.