Trend Micro ServerProtect relay.dll Chunked Overflow Vulnerability iDefense Security Advisory 12.14.05 www.idefense.com/application/poi/display?id=354&type=vulnerabilities December 14, 2005 I. BACKGROUND Trend Micro Inc.'s ServerProtect provides antivirus scanning with centralized management of virus outbreaks, scanning, patter file updates, notifications and remote installations. More information about the product set is available at: www.trendmicro.com/en/products/file-server/sp/evaluate/overview.htm II. DESCRIPTION Remote exploitation of a heap overflow in Trend Micro Inc.'s ServerProtect Management Console allows remote attackers to execute arbitrary code with the privileges of the underlying web server. The problem specifically exists within the relay.dll ISAPI application upon processing of large POST requests with "wrapped" length values, example: POST /TVCS/relay.dll HTTP/1.0 Transfer-Encoding: chunked 80000000 [ 50,000 bytes or so ] The above example request will create an exploitable heap corruption providing the attacker with a near arbitrary 4-byte overwrite. By overwriting the address of a soon to be called function the attacker can seize CPU control and eventually execute arbitrary code. III. ANALYSIS Successful exploitation of the described issue allows remote attackers to execute arbitrary code with the privileges of the underlying web server. Exploitation does not require credentials, thereby exacerbating the impact of this vulnerability. IV. DETECTION iDefense has confirmed the existence of this vulnerability in Trend Micro ServerProtect for Windows Management Console 5.58 running with Trend Micro Control Manager 2.5/3.0 and Trend Micro Damage Cleanup Server 1.1. It is suspected that earlier versions and versions for other platforms are vulnerable as well. V. WORKAROUND Employ firewalls, access control lists or other TCP/UDP restriction mechanism to limit access to the vulnerable system on the configured port, generally TCP port 80. VI. VENDOR RESPONSE "Trend Micro has recently become aware of a vulnerability related to the Microsoft Foundation Classes (MFC) static libraries used by Trend Micro products to create Internet Server Application Programming Interface (ISAPI) programs for IIS user interfaces. Under certain heavy load conditions, the MFC ISAPI produces invalid arguments, which can create an access violation, and thus a denial of service to users. The original MFC vulnerability was reported and patched in 2002 by Microsoft, however, in April 2005, Microsoft published new solutions, and vendors were required to rebuild programs to link to the new library. During this transition period, manual solutions are available through Trend Micro technical support for customers wishing to take precautionary measures, in the unlikely event of an exploit targeted at the MFC vulnerability. The potential impact to Trend Micro products is limited to some versions of InterScan eManager, InterScan Web Protect, OfficeScan, and Control Manager. Many of these products will be updated in the next version release. For now, use the workarounds provided: Option I: Use the Microsoft URLScan Tool 1. Download any of the following: Note: The tool prevents a potential thread by rejecting the specified requests. * URLScan 2.5 (for IIS 6.0) * IIS Lockdown Tool 2.1 (for IIS 4.0 or 5.0) 2. Run the URLScan tool. The urlscan folder is automatically created in the C:WINDOWSsystem32inetsrvurlscan directory. 3. Open Windows Explorer and go to the C:WINDOWSsystem32inetsrvurlscan directory. 4. Find the URLScan.ini file and open with a text editor like Notepad. 5. Find the [AllowExtensions] section and add the following file extensions: * .exe * .ini * .dat * .asp 6. Find the [DenyHeaders] section and add the transfer-encoding: parameter. 7. Find the [Options] section and change the value of UseAllowExtensions to "0". 8. Under [DenyExtensions], remove the following file extensions: * .exe * .ini * .dat * .asp 9. Save the changes and close the file. 10. Stop and start the Web service. Option II: Change build environments Trend Micro recommends changing the build environments to Visual C++ 6.0 with Service Pack 6." VII. CVE INFORMATION The Common Vulnerabilities and Exposures (CVE) project has assigned the name CVE-2005-1929 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 06/03/2005 Initial vendor notification 06/05/2005 Initial vendor response 12/14/2005 Public disclosure IX. CREDIT The discoverer of this vulnerability wishes to remain anonymous. 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.