Microsoft's Internet Explorer has a longstanding reputation for poor security, but it's now bad enough that you could be attacked just by having it on your PC. Security researcher John Page has revealed an unpatched exploit in the web browser's handling of MHT files (IE's web archive format) that hackers can use to both spy on Windows users and steal their local data. As Windows opens MHT files using IE by default, you don't even have to run the browser for this to be a problem -- all you have to do is open an attachment sent through chat or email.