(5S Step 2 — Schützen) What does antivirus software do, and what is the one condition for it to be useful at all?

It scans for and blocks malware in files, web traffic, and email — but only if it's kept automatically up to date.

Antivirus protects against viruses, worms, trojans, ransomware, etc., and inspects internet traffic and email for threats. The non-negotiable condition: it must update automatically and regularly — an outdated scanner doesn't recognise new malware and is effectively useless.

Practical notes from the source:

• On Windows 10+, the built-in Microsoft Defender is a solid, low-maintenance option.
• Run a full system scan periodically, not just on-access checks.
• Android benefits from a scanner; iOS is a closed system and generally doesn't need one.

Tip: AV is necessary but not sufficient — it catches known/known-ish threats. It won't save you from a fresh zero-day or from you typing your password into a phishing page.