NGSSoftware Insight Security Research Advisory
Name: Windows Help System Buffer Overflow
Systems: Windows XP,2000,NT,ME and 98
Severity: High Risk
Category: Buffer Overflow Vulnerability
Vendor URL: http://www.microsoft.com/
Author: David Litchfield ([email protected])
Advisory URL: http://www.ngssoftware.com/advisories/ms-winhlp.txt
Date: 2nd October 2002
Advisory number: #NISR02102002
Introduction
The Windows Help system includes an ActiveX control known as the HTML Help
Control, hhctrl.ocx. The "Alink" function of this control is vulnerable to a
buffer overflow that can be exploited to gain control of the user's machine.
Details
By providing an overly long parameter to the vulnerable function an internal
buffer is overflowed and program control structures can be overwritten
allowing an attacker to remotely gain control of their victims PC. This
could be done by enticing the victim to a website that contained a webpage
that exploits the vulnerability or by sending the victim an HTML mail. When
opened in Outlook the overflow will be triggered.
Fix Information
Microsoft have produced a patch which is available from their web site.
More details are available from
http://www.microsoft.com/technet/treeview/?url=/technet/security/bulletin/MS
02-055.asp