Denial of Service Attacks: Threats and Methodologies

SCOPE AND DEFINITIONS The provision of any service requires the utilisation of resources. In a digital context these resources might be processor cycles, memory capacity, disk space or communications bandwidth. A Denial of Service (DoS) attack implies either the removal of those resources by some external event or their pre‐emption by a competing process; this should be understood to include rerouting or replacing a service. The sole objective of a DoS attack is thus to prevent the normal operation of a digital system in the manner required by its customers and intended by its designers. As such, DoS attacks on the mission‐critical or business‐critical infrastructure systems of financial, commercial or other enterprises offer the potential for sabotage, blackmail or extortion operations.