October 23, 2017

LinkedIn can be tricked into revealing personal email addresses

linkedin(LiveHacking.Com) – Benjamin Caudill and Bryan Seely, founders of Rhino Security, have discovered an unintentional side effect of LinkedIn’s obsession with making sure you are “linked” with just about everyone you have had contact with. According to the new research, which was published in part by Brian Krebs, it is possible to troll LinkedIn and discover the email addresses of public figures including leading CEOs, celebrities and company executives.

On a normal day LinkedIn will only let you connect with users that you claim to know professionally or personally. If you don’t know some you can get an introduction via a common third party. To ensure that you are linked to everyone you know LinkedIn will optionally trawl through your Google/Yahoo/Hotmail address book to see if anyone in your address book is already using LinkedIn. Sounds great, very helpful.

The problem is that if you start to create fake email addresses in your list of contacts then LinkedIn will helpfully show you the profiles of users with addresses that match your address book. This is because LinkedIn assumes that if you have their email address then you must know the person.

Now all you need to do is populate your address book with hundreds of combinations of email addresses based on people’s names, and then add @gmail.com or @yahoo.com etc on to the end.

When you import the list of names then LinkedIn will not only show you the profiles which match the addresses, it will also tell you which addresses don’t match any known profiles. If you got lucky and found the address of a high profile user then you just need to use a process of elimination to whittle down the list of emails that didn’t match a profile and you can discover the private email address of the target LinkedIn user.

To prove their point Cludill and Seely discovered the email address of Mark Cuban, the owner of the Dallas Mavericks. Seely said they found success in locating the email addresses of other celebrities using the same method about nine times out of ten.

“We created several hundred possible addresses for Cuban in a few seconds, using a Microsoft Excel macro,” Seely said. “It’s just a brute-force guessing game, but 90 percent of people are going to use an email address that includes components of their real name.”

According to LinkedIn the company will be implementing a couple of changes over the next few weeks to alter the way the service handles email addresses.

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