Microsoft Releases Security-Enhanced Internet Explorer 8

The newest version of Internet Explorer 8 is basically complete: Microsoft this week made available for download a prerelease version of the long-awaited browser, which includes more built-in security.

Among IE8's new security features is protection against so-called clickjacking attacks, in which an attacker could slip a malicious link invisibly onto a Web page, without a user realizing he had clicked on it or had been compromised. For example, a commonly used button on a Website could be loaded with this attack unbeknown to the Website operator or the user hitting the button.

Microsoft says its new clickjacking protection feature lets Websites safeguard their sites and visitors without browser add-ons. The feature uses a "tag," or HTTP header, that attaches to the Web pages. But security experts say this form of protection works only for Websites that deploy the feature, not the browser users themselves.

Robert "RSnake" Hansen, who along with fellow security researcher Jeremiah Grossman first revealed the dangers of clickjacking attacks, doesn't think the new Microsoft browser feature will help stop clickjacking attacks. "It doesn't protect consumers -- it only protects Websites that know about the header and output the header on the pages they want to protect," Hansen says. "So while it's a nice gesture, it is unlikely to make any real difference given the incredible array of applications that are vulnerable."

Hansen says the feature won't help sites that require iFrame-based banner advertising, for instance. "Most banner advertisers live within iFrames, and they make their business on having people click on their links within those iFrames. If any of that functionality were to break, so, too, would their entire business model," says Hansen, founder of SecTheory LLC. "So they will need to continue to be vulnerable to clickjacking, lest their business would disintegrate for all IE users."

He says he doesn't expect the feature to be widely adopted by Website owners.

Microsoft also included its much-anticipated cross-site scripting (XSS) filter in the so-called Release 1 Candidate version of IE8, which is almost finished except for some final input from users. The XSS Filter basically detects malware running on a Website.

"I think the XSSFilter is a very good thing. The approach raises the difficulty bar, but certainly does not make things impossible," says Grossman, who is CTO of WhiteHat Security. "It's one of those things that's very hard to break the first time, and then easy from then on."

Other security features in IE8 are the SmartScreen filter, which catches malicious Websites and warns the user if he or she is downloading malware inadvertently; and InPrivate browsing, which ensures that browsing history, temporary Internet files, form data, cookies, usernames, and passwords aren't left behind in the browser history. InPrivate filtering lets you set options for what information about browsing behavior can be tracked by third-party Websites -- a feature that is enabled on a per-browsing-session basis.

The browser also has extra protection from phishing sites with its Domain Highlighting feature, which highlights the domain name in the address bar in black, and colors the rest of the URL string in gray to show the actual origin of the site. The Data Execution Prevention feature stops some types of code from writing to executable memory space.

As for clickjacking protection, Hansen advises users to run Mozilla's Firefox browser, along with NoScript, LocalRodeao, and RequestPolicy add-ons. "For companies, your best bet is to follow Microsoft's advice to send the header for IE users, take advantage of frame-busting code wherever possible, and make every page URL unique per user," he says.

Still, there's no guaranteed way to stop clickjacking. "The fact is that clickjacking is a seriously tough problem to solve," Grossman says.

Giorgio Maone, who developed the NoScript browser add-on, says IE8 signals that Microsoft may be changing its tune when it comes to browser security. "With IE8, Microsoft got an impressive boost in courage and attention toward emergent threats, such as XSS, while previously there was a sort of 'the Web is too much broken to be fixed in a browser' attitude," Maone says.

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