Kaminsky Creates Clickjacking-Killer

DEF CON 23 -- Las Vegas -- Renowned security expert Dan Kaminsky here this week unveiled his latest project: a solution to eradicate so-called clickjacking attacks that plague the Web.

Kaminsky hopes to have his IronFrame approach support the World Wide Web Consortium's (W3C) UI Security specification, and ultimately ensure that clicking on compromised ads and other outside content on a website doesn't silently redirect users to malicious websites in clickjacking attacks. Clickjacking is where concealed and malicious content and links on a website are layered atop legitimate ones, unbeknownst to the user and the website operator.

"We have this problem where, because of the Web security model, you don't actually know what's on your web page. You just pull resources in from around the Net," Kaminsky said in an interview prior to his DEF CON 23 presentation here. "This [content] might be good, bad; maybe … by someone modifying it. This entire class of attacks is called clickjacking."

With IronFrame, Kaminsky says he's using the browser's "graphics model to present the right stuff to the user" rather than the modified content injected by cyber criminals. A PayPal box saying "Want to spend $1000?" could be altered with an icon atop it that changes the link to say $1, for example, he says.

IronFrame operates like a Jenga building-block model, moving the bottom layer of graphics content to the top layer so the browser doesn't even see the phony and malicious layer. It’s a way to end clickjacking "by design," he says.

"It's never been clear how to efficiently validate what the user sees" on the page, he says. "What I'm showing is that if you move the obscured layer to the top of the stack -- after JavaScript but before the GPU -- you can know what the user sees."

The browser to date doesn't even necessarily know what content is being presented to the user, he says. "The browser says, 'hey, GPU: go render this and you figure it out,'" Kaminsky explains.

Kaminsky's solution basically ensures that the original content is rendered by the browser, not any content layered atop it by bad guys.

Kaminsky, who is chief scientist with WhiteOps Security, also built a JavaScript-based CPU monitor that illuminates how when web pages load slowly, it's often due to content hidden within a rogue iFrame.

"Hackers can fix things. We don't just break things," he says. "I like looking at how things actually work and taking that knowledge and using it to make things better.

"We're hackers: we're not afraid to get into how things work. Let's use that knowledge and fearlessness and make things work better," he says.

Kaminsky says his open-source project is in the early stages. "I don't have it perfectly"  yet, he says.

"My goal is to go to a Blink developer [for example] and say we need this, it's feasible, here's a string, a beginning" to build on, he says.