Have you ever tried to buy tickets for a huge event and found that the seller’s website has collapsed under the weight of thousands of people all trying to do the same thing at the same time?
The ticket site falls over – usually temporarily – because the server is overloaded with traffic it doesn’t have the capacity for.
Criminal Distributed Denial of Service attacks – DDoS, for short – exploit the same principle. When a DDoS attack targets a business, it floods it with internet traffic in an attempt to overwhelm the system and force it to fail. This results in the business and its customers being unable to access services. That may trigger a temporary failure, or it could be more serious.