This article originally appeared on The Wall St. Journal .
The following is a guest post from Matt Leibowitz.
Matt Leibrowitz is a senior software engineer at Amazon.
He leads the team of security engineers working to help our customers improve their security, both in terms of securing their personal data and in the cloud.
Matt is also the author of the ebook “How to Hack the Web” and the blog “How I Did It”.
You can follow him on Twitter @mattthewleibowitz and on his website.