A vulnerability has been identified in Microsoft Internet Explorer, which could be exploited by attackers to cause a denial of service. This flaw is due to a NULL pointer dereference error in the HTML Help Control "HHCtrl.ocx" when processing a "Click()" method, which could be exploited by attackers to crash a vulnerable browser by tricking a user into visiting a malicious web page.

Affected Products

Microsoft Internet Explorer 5.01 Service Pack 4 on Microsoft Windows 2000 Service Pack 4
Microsoft Internet Explorer 6 Service Pack 1 on Microsoft Windows 2000 Service Pack 4
Microsoft Internet Explorer 6 Service Pack 1 on Microsoft Windows XP Service Pack 1
Microsoft Internet Explorer 6 for Microsoft Windows XP Service Pack 2
Microsoft Internet Explorer 6 for Microsoft Windows Server 2003
Microsoft Internet Explorer 6 for Microsoft Windows Server 2003 Service Pack 1
Microsoft Internet Explorer 6 for Microsoft Windows Server 2003 (Itanium)
Microsoft Internet Explorer 6 for Microsoft Windows Server 2003 with SP1 (Itanium)
Microsoft Internet Explorer 6 for Microsoft Windows Server 2003 x64 Edition
Microsoft Internet Explorer 6 for Microsoft Windows XP Professional x64 Edition
Microsoft Internet Explorer 6 Service Pack 1 on Microsoft Windows 98
Microsoft Internet Explorer 6 Service Pack 1 on Microsoft Windows 98 SE
Microsoft Internet Explorer 6 Service Pack 1 on Microsoft Windows Millennium Edition

Solution

VUPEN Security is not aware of any vendor-supplied patch.

References

http://www.vupen.com/english/advisories/2006/2952
http://browserfun.blogspot.com/2006/07/mobb-22-internethhctrl-click.html

Credits

Vulnerability reported by Alex F.

Changelog

2006-07-25 : Initial release

Feedback

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