The DNS flaw refers to the way web page addressing is handled on the Internet, and the one who discovered it by accident was Dan Kaminsky. An attacker can take advantage of this security issue and redirect the user to any site, no matter what address the user is trying to access. It would be a great opportunity for someone with malicious intent to set up a fake site and get your private data (phishing). The worst thing is that the flaw affects all platforms, no matter the vendor they came from. A fix was issued by the industry yesterday, the 9th of July.

DNS (short for Domain Name System) works like this: whenever you type an address into your browser, that name is converted into a series of numbers so that your request can be properly routed. For example the ICANN.org web page turns into 208.77.188.103.

Dan Kaminsky comments: "It is a fundamental issue affecting the design. Because the system is behaving exactly like it is supposed to behave, the same bug will show up in vendor after vendor after vendor. This one bug affected not just Microsoft ... not just Cisco, but everyone. People should be concerned but they should not be panicking."

Phishing stands to win the most from such a vulnerability. Instead of accessing your bank's web page for example, you will be redirected to another site that looks the same, but was set up by someone with malicious intentions. You will not be aware of the fact that you have been redirected and you will provide the phishing site with all your private information.

Rich Mogul from Securiosis comments: "It's a very fundamental issue with how the entire addressing scheme of the Internet works. You'd have the Internet, but it wouldn't be the Internet you expect. (Hackers) would control everything."

This is the first time that a vulnerability of this magnitude comes to light. The industry has been working hard for the past six months and a patch has been made available.