An attack on the availability of data resources ("denial of service") aims to prevent users from using necessary and normally available functions or devices. This type of attack is often connected to the use of distributed resources, with the attacker placing such high demands on these resources that other users can no longer access them. IT systems are typically highly interdependent, as well. This means that a shortage of resources on one server will quickly affect others. Shortages of CPU time, storage space, or bandwidth, for example, can be artificially induced. This can lead to services or resources no longer being available.