McAfee Security Center MCINSCTL.DLL ActiveX Control File Overwrite iDefense Security Advisory 12.20.05 http://www.idefense.com/intelligence/vulnerabilities/display.php?id=358 December 20, 2005 I. BACKGROUND McAfee VirusScan is an anti-virus software. More information is available from the vendor website: http://www.mcafee.com/myapps/ II. DESCRIPTION Remote exploitation of an access control vulnerability in McAfee Security Center allows attackers to create or overwrite arbitrary files. The vulnerability specifically exists due to a registered ActiveX control failing to restrict which domains may load the control for execution. MCINSCTL.DLL as included with McAfee Security Center exports an object for logging called MCINSTALL.McLog. The McLog object is designed to allow Security Center to log to a file through the StartLog and AddLog methods. McAfee fails to restrict the ActiveX control from being loaded in arbitrary domains. As such, attackers can create a specially crafted web page utilizing the McLog object to create arbitrary files. This attack can lead to arbitrary code execution by a remote attacker. III. ANALYSIS Successful exploitation of this vulnerability allows attackers to create or append to arbitrary files. An attacker can write to a startup folder to execute arbitrary code during the next reboot or logon session. A user will not be required to authorize the object instantiation since the object is within a signed ActiveX control. A typical exploitation scenario would require an attacker to convince a targeted user to visit a malicious website. This vulnerability hints at a new class of vulnerabilities that occur due to developers not using the IObjectSafetySiteLock() API to restrict domains that can load a particular ActiveX control. Vendors who distributed third-party ActiveX controls should be sure to use the IObjectSafetySiteLock() API in their applications. IV. DETECTION McAfee Security Center is a component that is distributed with various McAfee products. The following products have been confirmed to contain a vulnerable mcinsctl.dll component in their distribution: ? McAfee VirusScan (mcinsctl.dll 4.0.0.83) V. WORKAROUND iDefense is unaware of any effective workarounds at this time. VI. VENDOR RESPONSE "McAfee previously released updates to SecurityCenter that resolve this issue. All active McAfee SecurityCenter users, by default, should have automatically received the update, and will now have the fix for this vulnerability already installed on their computers. To manually check for updates, users can right-click the McAfee system tray icon (white M on red background) and select 'Updates'. In the resulting dialogue box, they should click 'Check Now' to check the server for updates. The user will be walked through the update process or be notified that all software is up to date. If a user has not yet registered, a registration web page or the registration wizard will pop-up, guiding the user through the update process. McAfee's key priority is the security of our customers. In the event that a vulnerability is found within any of McAfee's software, we have a strong process in place to work closely with the relevant security research group to ensure the rapid and effective development of a fix and communication plan." VII. CVE INFORMATION The Common Vulnerabilities and Exposures (CVE) project has assigned the name CVE-2005-3657 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 11/15/2005 Initial vendor notification 11/16/2005 Initial vendor response 12/20/2005 Coordinated public disclosure IX. CREDIT iDefense credits Peter Vreugdenhil with the discovery of this vulnerability. Get paid for vulnerability research http://www.iDefense.com/poi/teams/vcp.jsp Free tools, research and upcoming events http://labs.iDefense.com X. LEGAL NOTICES Copyright © 2005 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 (at) iDefense (dot) com [email concealed] 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.