A DDoS attack occurs when multiple computers attack the same target together. For large-scale attacks, DDoS attackers often use a botnet - a group of hijacked devices connected to the Internet. Attackers exploit security vulnerabilities and device weaknesses to control multiple devices with management and control software. After gaining control, the attacker can command his botnet to launch a DDoS attack on the target. In this case, the infected devices also become victims of the attack.