If you're using Apple's Safari browser, PayPal has some advice for you: Drop it, at least if you want to avoid online fraud.

Safari doesn't make PayPal's list of recommended browsers because it doesn't have two important anti-phishing security features, according to Michael Barrett, PayPal's chief information security officer.

"Apple, unfortunately, is lagging behind what they need to do, to protect their customers," Barrett said in an interview. "Our recommendation at this point, to our customers, is use Internet Explorer 7 or 8 when it comes out, or Firefox 2 or Firefox 3, or indeed Opera."

Safari is the default browser on Apple's Macintosh computers and the iPhone, but it is also available for the PC. Both Firefox and Opera run on the Mac.

Unlike its competitors, Safari has no built-in phishing filter to warn users when they are visiting suspicious Web sites, Barrett said. Another problem is Safari's lack of support for another antiphishing technology, called Extended Validation (EV) certificates. This is a secure Web browsing technology that turns the address bar green when the browser is visiting a legitimate Web site.

When it comes to fighting phishing, "Safari has got nothing in terms of security support, only SSL, that's it," he said. Apple representatives weren't immediately available to comment on this story.

An emerging technology, EV certificates are already supported in Internet Explorer 7, and they've been used on PayPal's Web site for more than a year now. When IE 7 visits PayPal, the browser's address bar turns green -- a sign to users that the site is legitimate. Upcoming versions of Firefox and Opera are expected to support the technology.

But EV certificates have their critics. Last year, researchers at Microsoft and Stanford University published a study showing that, without training, people were unlikely to notice the green address-bar notification provided by EV certificates.

Still, Barrett says data compiled on PayPal's Web site show that the EV certificates are having an effect. He says IE 7 users are more likely to sign on to PayPal's Web site than users who don't have EV certificate technology, presumably because they're confident that they're visiting a legitimate site. (Compare Data Leak Protection products)

Over the past few months, IE 7 users have been less likely to drop out and abandon the process of signing on to PayPal, he said. "It's a several percentage-point drop in abandonment rates," he said. "That number is... measurably lower for IE 7 users."

Opera, IE, and Firefox are "safer, precisely because we think they are safer for the average consumer," he added. "I'd love to say that Safari was a safer browser, but at this point it isn't."

The IDG News Service is a Network World affiliate.