Denial of Service Attack (DoS)

A Denial of Service Attack is a type of attack against a computer system or website.  It usually involves flooding the site with traffic or attacking a specific vulnerability resulting in a slowed or unavailable system or resource or restricted access. Not all Denial of Service Attacks are malignant. Cyber insurance policies may or may not cover a denial of service attack, and if coverage is granted, the definition of what constitutes a denial of service attack varies.
Also read about: Distributed Denial of Service attack.