Public Vulnerability Reports

Trend Micro ServerProtect relay.dll Chunked Overflow Vulnerability

12.14.05

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

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.

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.

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.

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.

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."

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.

DISCLOSURE TIMELINE

06/03/2005 Initial vendor notification
06/05/2005 Initial vendor response
12/14/2005 Public disclosure

CREDIT

The discoverer of this vulnerability wishes to remain anonymous.

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LEGAL NOTICES

Copyright © 2005 Verisign, Inc.

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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.