Security vendors like VeriSign consider a new technology called EV SSL an important measure against phishing attacks. But two recent items suggest it will do little to stop skilled conmen from spoofing trusted websites.

Exhibit A was this post from network services company Netcraft, which documents a recently discovered cross-site scripting error on the popular open source website SourceForge. The gaping hole allowed unauthorized data to be injected into the website, opening up a new browser window.

It just so happens that SourceForge is one of the 5,000 or so websites using EV SSL, which is short for Extended Verification Secure Sockets Layer. It works just like plain-vanilla SSL except that it requires website operators to take additional steps to verify their identity before receiving an electronic certificate.

Sites that use the technology show up in green in a browser's address bar. They're designed to give users additional confidence that the site is not an impostor under the control of bad guys.

And yet, as the SourceForge goof made clear, there's no guarantee at all that sites showing up green aren't under the control of unauthorized parties. A cross-site scripting error on the right site can prove a bonanza to phishers because it allows them to inject rogue content into a trusted site - for instance a dialog box that instructs the visitor to enter his login credentials. The concern is the green bar will cause end users to drop their guard by giving them a false sense of security.

Exhibit B came in the form of a recently released survey by NetBenefit that finds 70 per cent of UK online shoppers don't understand what a green browser bar is anyway.

Not that everyone is convinced EV SSL is a waste. According to this article from Network World, the lack of support for EV SSL is one reason PayPal is recommending its users steer clear of Apple's Safari browser. It reports that people using EV SSL are more likely to actually log in to PayPal than those who don't, presumably because they have greater confidence.

Still, it's not clear exactly what problem EV SSL is supposed to solve. While it's theoretically possible for phishing sites to use SSL, reports of SSL-protected sites spoofing PayPal or other sensitive websites are rare, if not nonexistent. We think we'll wait out the the rush to acquire extended certificates for the time being. ®