Denial of Service Attacks
A denial of service attack (also known as DoS) is an attempt to make a device (computer or any other device attached to a network) unavailable by either completely shutting it down or making it slow, thus making the resource unavailable to the intended users. Sometimes a large number of computers are involved in an attack (forming a Botnet), that attack are known as Distributed Denial of Service (DDoS) Attacks.
Recent DoS attacks victims were some of the big names including Paypal, MasterCard, Visa and the list goes on.
Although a DoS attack, doesn’t generally breaches the target organisation’s security (in most of the cases, by causing a server overload), though it does causes it heavy damage, by not being available to the legitimate users. The consequences can be worse, if the victim is a Bank or Payment Gateways.