Learn in the textbookTechnical and Physical Vulnerabilities
DefinitionAn act of obstruction (妨害行為) is a deliberate human act that keeps an information system or business operation from running normally.
ExplanationBesides physical means such as cutting the power or a line, it can also be carried out over the network, as in a DoS attack (DoS攻撃) that floods a service with traffic until it stops. Both kinds undermine availability, and entry/exit control and traffic monitoring are the safeguards.
AnalogyIt is like a crowd camping at a shop's entrance and blocking the way so real customers cannot get in. The building is untouched, yet business stops.