Scripting flaws pose severe risk for IE users

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By John Leyden • Get more from this author

Posted in Security, 25th November 2003 21:29 GMT

A set of five unpatched scripting vulnerabilities in Internet Explorer creates a mechanism for hackers to compromise targeted PCs.

The vulnerabilities, unearthed by Chinese security researcher Liu Die Yu, enable malicious Web sites and viruses to bypass the security zone settings in IE6. Used in combination, the flaws might be exploited to seize control of vulnerable PCs.

Proof of Concept exploits have been released by Liu Die Yu to validate his warnings.

Microsoft has yet to patch the flaws. But users can protect themselves against the flaws by disabling active scripting or by using an alternative browser.

Thomas Kristensen, CTO of security Web site Secunia, told The Register that the five distinct vulns could used in combination to install executables (viruses, Trojans and porn diallers). Secunia describes the vulnerabilities as "extremely critical".

Despite this, Kristensen warns that Microsoft is unlikely to break its newly instituted monthly release cycle to release a stand-alone IE patch unless a vulnerability was widely exploited. Pending the availability of a patch, Secunia advises all IE users to disable active scripting.

The drawback of this workaround is that with some Web sites certain functions won't work unless scripting is enabled. IE users should define any sites they need to use as trusted so that they can continue to use scripting on those sites alone, Kristensen advised.

Secunia's advisory is here. ®