Much of today's security news is about the latest hacks by cyber criminals, and how they exploited some obscure software vulnerability to break into systems and wreak havoc.

But often a breach will start with something more mundane. Ever since people started sending emails and using the Internet, they have been making the same careless mistakes that leave sensitive information and the business at risk. Sure people are under pressure, they're in a hurry, and they need to get the job done, but sometimes they let their guard down.

No matter how much you nag people, plead with them and warn them, these mistakes and risky behaviors never seem to end. In this slideshow, Daren Glenister, field chief technology officer, Intralinks, has identified five all-too-common mistakes users need to be careful to avoid.