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iDEFENSE Security Advisory 04.13.04 - Microsoft Help and Support Center Argument Injection Vulnerability
From: idlabs-advisories () idefense com
Date: Tue, 13 Apr 2004 13:37:47 -0400
Microsoft Help and Support Center Argument Injection Vulnerability iDEFENSE Security Advisory 04.13.04 www.idefense.com/application/poi/display?id=100&type=vulnerabilities April 13, 2004 I. BACKGROUND Help and Support Center is a feature of Microsoft Windows that enables users to download and install software updates, check hardware compatibility and perform other system related tasks. II. DESCRIPTION Exploitation of an argument injection vulnerability in the Help and Support Center feature of Microsoft Corp.'s Windows operating system allows remote attackers to execute arbitrary code. HCP URIs are handled via the following command as defined in the registry key HKLM\SOFTWARE\Classes\HCP\shell\open\command: "C:\WINDOWS\PCHealth\HelpCtr\Binaries\HelpCtr.exe" -FromHCP -url "%1" The %1 is replaced by the argument to the HCP:// URI. By embedding quotes in the argument, it is possible to insert new arguments to the command. For example: HCP://" -url "../../unreachable.htm When the %1 is substituted in, this gives: C:\WINDOWS\PCHealth\HelpCtr\Binaries\HelpCtr.exe -FromHP -url "HCP://" -url "../../unreachable.htm" An attacker can compromise a vulnerable system by crafting a URL to inject scripting code into a pre-existing file such as System\errors\connection.htm. The scripting code executes under the "My Computer" zone. III. ANALYSIS Successful exploitation allows an attacker to remotely execute arbitrary code under the context of the My Computer zone. Script code executing with such privileges can be crafted to retrieve and execute arbitrary third-party code, thereby leading to further compromise. IV. DETECTION iDEFENSE has confirmed the existence of this vulnerability in the latest versions of Windows Server 2003 and Windows XP. V. WORKAROUNDS As stated in Microsoft advisory MS03-044, the HCP protocol can be unregistered, thereby preventing successful exploitation. This can be accomplished by deleting the key 'HKEY_CLASSES_ROOT\HCP' using the windows registry editor. VI. VENDOR RESPONSE Microsoft has issued the following security bulletin to address this vulnerability: Microsoft Security Bulletin MS04-011 Security Update for Microsoft Windows (835732) http://www.microsoft.com/technet/security/bulletin/ms04-011.mspx VII. CVE INFORMATION The Common Vulnerabilities and Exposures (CVE) project has assigned the name CAN-2003-0907 to this issue. This is a candidate for inclusion in the CVE list (http://cve.mitre.org), which standardizes names for security problems. VIII. DISCLOSURE TIMELINE [prior] Exploit disclosed to vendor by contributor January 12, 2004 Exploit acquired by iDEFENSE January 12, 2004 iDEFENSE clients notified January 19, 2004 iDEFENSE Initial contact with vendor January 23, 2004 Initial vendor reply April 13, 2004 Coordinated public disclosure IX. CREDIT Jouko Pynnönen (http://iki.fi/jouko) is credited with this discovery. Get paid for vulnerability research http://www.idefense.com/poi/teams/vcp.jsp IX. LEGAL NOTICES Copyright © 2004 iDEFENSE, Inc. Permission is granted for the redistribution of this alert electronically. It may not be edited in any way without the express written consent of iDEFENSE. If you wish to reprint the whole or any part of this alert in any other medium other than electronically, please email customerservice () idefense com for permission. Disclaimer: The information in the advisory is believed to be accurate at the time of publishing based on currently available information. Use of the information constitutes acceptance for use in an AS IS condition. There are no warranties with regard to this information. Neither the author nor the publisher accepts any liability for any direct, indirect, or consequential loss or damage arising from use of, or reliance on, this information. _______________________________________________ Full-Disclosure - We believe in it. Charter: http://lists.netsys.com/full-disclosure-charter.html
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