Your Private Browsing Isn’t as Incognito as You Want It to Be
Your computer can store clues
By Rob Verger
There’s no shame in firing up a private browsing window from time to time, whether it’s to visit a NSFW website or just to protect your personal information while checking your email on a public computer. But while private browsing modes do their best to erase your tracks, they can also leave digital clues behind.
The virtue of a feature like Chrome’s Incognito Mode, of course, is that whoever uses that computer after you shouldn’t be able to see the sites you’ve visited, because the browser doesn’t record your history. But traces of your browsing can still remain on your computer after you’ve closed that Incognito window, a phenomenon that can happen in a couple different ways, says Frank Wang, a computer science doctoral candidate at MIT.
One vulnerability has to do with something called a domain name service (or DNS) request. When a browser connects to a website — say, PopSci.com — it needs to translate those letters into numbers, and that process can leave footprints in your operating system, Wang says, in a place called the DNS cache. If a knowledgeable person got access to your machine, they could exploit this vulnerability to figure out what sites you’ve visited. “It’s not very hard actually,”…
