What cyber security actually protects

Cyber security is often described as "protecting computers," but that undersells it. What's really being protected is three things, known as the CIA triad:

Confidentiality

Only the people who should see information can see it. A leaked customer database or a screenshot of someone else's inbox is a confidentiality failure.

Integrity

Information can be trusted to be accurate and unaltered. An attacker quietly changing an invoice's bank details before it's sent is an integrity failure, even though nothing was "stolen."

Availability

Systems and data are there when needed. A ransomware attack that encrypts every file on a company's server is primarily an availability failure, the data usually isn't gone, it's just been made unreachable.

Almost every security control you'll ever encounter, from a password policy to a backup schedule, exists to protect one or more of these three things.