A DoS (Denial of Service) attack is a type of cyberattack where an attacker seeks to make a network service, website, or system unavailable to its intended users by overwhelming it with a flood of traffic or other resource-draining activities. This can cause the targeted service to crash or become so slow that it’s inaccessible. In a typical DoS attack, a single source is used to launch the attack. When multiple systems are used in coordination to perform the attack, it’s called a DDoS (Distributed Denial of Service) attack. The goal of a DoS attack is often to disrupt normal operations and cause downtime for the targeted service or organization.