There's a trivial way for drive-by exploit developers to bypass the security sandbox in almost all versions of Internet Explorer, and Microsoft says it has no immediate plans to fix it, according to researchers from Hewlett-Packard.
The exploit technique, laid out in a blog post published Thursday, significantly lowers the bar for attacks that surreptitiously install malware on end-user computers. Sandboxes like those included in IE and Google Chrome effectively require attackers to devise two exploits, one that pierces the sandbox and the other that targets a flaw in some other part of the browser. Having a reliable way to clear the first hurdle drastically lessens the burden of developing sophisticated attacks.
The bypass technique "does give the attacker a significant advantage by giving them higher-level access than a typical exploit might in Internet Explorer, by allowing them to escape the sandbox," Robert "Rsnake" Hansen, a vice president at security firm WhiteHat Labs, wrote in an e-mail to Ars. "In practical terms this is a very important finding, because it can be tied into existing exploits that might otherwise not be able to escape the IE sandbox."