Downtime

Downtime is a period when a computer system is unavailable, so nobody can use the service it provides. During a security breach it is often a temporary, complete loss of service: the equipment is still there, but staff and customers cannot log in, view records or place orders.

Why a breach causes downtime

When an organisation discovers a breach, it needs time to investigate and fix it. The system may be deliberately shut down to stop malicious software spreading or to stop an attacker reaching other accounts. Staff might disconnect the network, check logs, remove the attacker's access, reset passwords and restore a clean backup. Until that work is finished, the service stays offline.

What happens during downtime

While systems are down, an organisation may be unable to operate normally or complete customer orders, so customers wait and income is lost. For example, a bicycle repair workshop uses one system for bookings, spare-part stock and card payments. If the system is switched off during an investigation, mechanics cannot check whether a part is in stock, and counter staff cannot take card payments or print collection notes. Repairs stall and orders wait until the system is available again.

Downtime is not the same as data loss: downtime is about the system being unavailable, not about data being lost, stolen or corrupted.