A DDOS attack (better known as a Distributed Denial of Service attack) is a type of web attack that seeks to disrupt the normal function of the targeted computer network. This is any type of attack that attempts to make this computer resource unavailable to its users. While this type of attack typically follows the same sorts of patterns, the definition of the term Distributed Denial of Service does not make any specific indications of how this type of attack is to be pulled off. What makes this type of attack "distributed" is the concerted efforts between a large number of disruptors all for the common goal of preventing web servers (and therefore websites) from functioning effectively at all. These users may be willing participants, or in some cases be tricked into downloading software that will use their terminal to aid in the offensive. All in all, regardless of the means, a DDOS attack is simply a combined effort to prevent computer systems from working as well as they should, typically from a remote location over the internet.
The most common method of attack is to send a mass saturation of incessant requests for external communication to the target. These systems are flooded with requests for information from non-users, and often non-visitors to the website. The goal of this attack is to create a large enough presence of false traffic such that legitimate web traffic intended for actual web users is slowed down and delayed. If this type of service becomes too slow, time sensitive information such as live video footage may be rendered entirely useless to legitimate end users.
For a DDOS to work effectively, the process has to be heavily automated on the attacker's end. Customized software is designed to flood these services with false traffic, and is run on as many computers as possible. There are a few instances in which this type of software was set up like a virus, infecting computers and taking control of their communication functions. These users unwillingly are aiding in a DDOS attack, sometimes without being the slightest bit aware of it. If there seems to be large delays in normal internet service, there may be outbound requests being made consuming your internet connections given throughput, and can sometimes be an indication of foul play. Users seeking to limit this risk should keep anti-virus software up to date, and scan frequently for these types of programs.
While there are few court cases on the books of Distributed Denial of Service perpetrators being held accountable for their actions, as well as the potential lost income for commercial websites, this type of activity almost always violates the terms of service and acceptable use policies of internet service providers, as well as often violating individual communication law within the nation. These types of attacks have become more and more prevalent as time goes on, and in many nation legislation is in the works, with hopes of criminal penalties for those involved with this sort of attack.
All in all, a DDOS attack is a very real threat to businesses and organizations across the world, and it's important that they be prepared in case some group of people decides to cause trouble for your organization. Being prepared to identify these types of threats is an important part of proper internet use, and should be a part of your daily life online.