The recent theft of a small number of digital certificates, used by Web browsers to verify the identity of secure Websites, has put Safari users at potential risk, according to security developer and research firm Intego. The security developer says it's due to a limitation in the way Apple's browser handles the validation of online identities.

Several days ago, hackers managed to successfully request fraudulent digital certificates for various popular Websites-including Google, Yahoo, Skype, and others-from an affiliate of Comodo, which is one of several companies that issues digital certificates.

Digital certificates are used by browsers to verify that the site on the other end of a secure connection is who they purport to be. In other words, when you visit your bank online or shop at Amazon, certificates make sure that it really is your bank or Amazon. Those certificates are issued by a certificate authority, like Comodo; as long as the browser trusts the issuer, it implicitly trusts the certificates it's given out. (In Safari, you can view the certificate of a secure site by clicking on the padlock icon in the top right corner of the window or on the company name in the location field.)

More: http://www.pcworld.com/article/223262/