How DDoS Attacks Work
A DDoS attack begins with a botnet. A botnet is a network of computers that were infected with malicious software designed for DDoS attacks and other nefarious uses. Users may be tricked into downloading the infected software through phishing emails, infected websites, and even social networks by taking advantage of known exploits in software and operating systems.
Once these computers are infected, the botnet "wrangler" can control all of these machines without the user’s knowledge remotely from one application. Once the botnet grows large enough, the network can be used to launch an attack against any target.
Once a botnet is ready, the attacker can send a start command that will have every machine in the botnet sending a flood of requests to the intended target. If the attack makes it past defenses, it can quickly overpower most systems causing service outages and possibly crashing servers.
Many attackers that have created botnets offer their services for a price on online and darknet marketplaces, giving potentially anyone the capability of launching a DDoS attack.