Zero-day

A zero-day is a software flaw that attackers find before the maker knows about it, so no fix exists yet when the attacks begin.

Zero-day: A zero-day is a security hole in software that the maker does not yet know about, or has not yet fixed. The name means the maker had zero days to prepare. Attackers can use it to break in even on a phone or computer that is fully updated.

Most people will never meet a zero-day directly, since attackers usually save them for important targets. But once the flaw becomes public, many criminals start copying the attack within days. This is why companies like Google and Apple suddenly release urgent updates, sometimes with a note that the flaw was already being used. Attackers may hide it inside a normal looking web page, image or message, so you need not even install anything.

For an ordinary Indian user, the lesson is to install updates fast, not weeks later. A patch is the fix for the flaw. Keeping automatic updates on, using the official app store and avoiding unknown links reduces the chance that a freshly discovered hole ever reaches you. If your phone is too old to receive updates, think about replacing it for banking use.

Tips

• Turn on automatic updates for Android, your apps and your computer.
• Install urgent security updates the same day, especially for the browser.
• Avoid unknown links and files, because most attacks still need you to tap something first.

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