denial of service

The prevention of authorized access to a system resource or the delaying of system operations and functions.

An attack that prevents or impairs the authorized use of information system resources or services.

The prevention of authorized access to resources or the delaying of time-critical operations. (Time-critical may be milliseconds or it maybe hours, depending upon the service provided).

when legitimate users are unable to access information systems, devices, or other network resources due to the actions of a malicious cyber threat actor. Services affected may include email, websites, online accounts (e.g., banking), or other services that rely on the affected computer or network. A denial-of-service condition is accomplished by flooding the targeted host or network with traffic until the target cannot respond or simply crashes, preventing access for legitimate users. DoS attacks can cost an organization both time and money while their resources and services are inaccessible.

No definition is given in NIST SP 800-171r3. The term is attested in use at 2 citations in that document; a definition is pending curation.