You are no doubt aware of phishing attacks. When emails arrive purporting to be from your bank or the tax office with an urgent message trying to prompt the recipient to click a login button. The login button links to a web page that looks like the official organisation but of course, is not and the site is trying to gain your login information so they can use it on the legitimate site to access your account.
Spear-phishing is more targeted. An example is where an email is sent from a person you know and potentially trust. It might even be a senior figure at your company. The email will ask for something quickly and again, his is an attempt to catch people whilst they are unwary and trick them into paying a fake invoice or revealing sensitive information.
Here is a snip from an email account and as you can see, we have a message flagged for high importance from the CEO. Naturally we open it and want to action this straight away.
Outlook (and the Outlook web app) try to catch these attacks and warn the user in a clear way.
When we open the email (and before we even hit reply), Outlook displays a prominent warning that, although the name is similar to someone we receive email from regularly, the email address is unusual.
This is a great improvement and will hopefully help to reduce these attacks which are easy to fall prey to.