The open source OpenSSL project revealed Monday a serious security vulnerability known as the “Heartbleed” bug that is used by two-third of the web to encrypt data, ie. to protect usernames, passwords and any sensitive information on secure websites. Yahoo is said to be the most exposed to Heartbleed but the company said it has fixed the core vulnerability on its main sites. There are several things you would need to do to check for Heartbleed bug and protect yourself from it, apart from changing your passwords. And according to the Tor project, staying away from the internet entirely for several days might be a good idea.