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Knowledge / IR hardening acsc-glossary

Backup

A copy stored somewhere else so you can restore after loss. If ransomware can reach it with the same credentials, it is not a backup.

3-2-13 copiesprod + 22 mediadisk + other1 off-siteoffline / immutableA backup you have never restored is a hope, not a control.

A backup is a copy of data kept elsewhere so you can put the original back after deletion, corruption, or a very bad Tuesday. Essential Eight calls this out because restore is the control, not the job that wrote to tape in 2014.

Offline, immutable, or a different identity plane. Test the restore on a calendar. Time how long until the business can work. That number is your real recovery time.

Fact source: ASD's ACSC glossary.