Scanning a link in the body of an email list an essential part of any security solution, though not everybody can do it. It's important because links that appear fine on delivery are often not. They are designed to detonate at the time of click. This is to evade security services.
Links, however, are not just in the body of emails. They're also in attachments, and that offers another avenue for hackers to hide links.
With Avanan, links inside attachments are replaced, so that the websites behind them are inspected every time the link is clicked by an end user.
Hackers will try anything to get what they want. By hiding malicious links within attachments, and only activating them post-click, they've set themselves up for success. By rewriting every link, including those in attachments, that avenue for hackers is now shut off.