Huge Security Holes in IE6 Discovered

Sunday, January 9th, 2005
by Chris Short

Some vulnerabilities have been discovered in Internet Explorer, which can be exploited by malicious people to compromise a user’s system, conduct cross-site/zone scripting and bypass a security feature in Microsoft Windows XP SP2.

1) Insufficient validation of drag and drop events from the “Internet” zone to local resources for valid images or media files with embedded HTML code. This can be exploited by e.g. a malicious web site to plant arbitrary HTML documents on a user’s system, which may allow execution of arbitrary script code in the “Local Computer” zone.

This vulnerability is a variant of:
SA12321

NOTE: Microsoft Windows XP SP2 does not allow Active Scripting in the “Local Computer” zone.

2) A security site / zone restriction error, where an embedded HTML Help control on e.g. a malicious web site references a specially crafted index (.hhk) file, can execute local HTML documents or inject arbitrary script code in context of a previous loaded document using a malicious javascript URI handler.

Successful exploitation may allow execution of arbitrary HTML and script code in a user’s browser session in context of arbitrary sites, or execution of local programs with parameters from the “Local Computer” zone using a HTML Help shortcut.

NOTE: This will bypass the “Local Computer” zone lockdown security feature in SP2.

3) A security site / zone restriction error in the handling of the “Related Topics” command in an embedded HTML Help control can be exploited by e.g. a malicious website to execute arbitrary script code in the context of arbitrary sites or zones.
…

I should point out that the current fix is:

Use another product.

So get FireFox.

Also, a quick check on Windows Update shows no fixes for this problem and I’ve yet to receive an e-mail from Microsoft’s security mailing list about the problem. Glad I don’t use IE6 anymore.