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                                 Delphis Consulting Plc
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                               Security Team Advisories
                                    [08/05/2000]


                             securityteam@delphisplc.com
                  [http://www.delphisplc.com/thinking/whitepapers/]
        
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Adv     :       DST2K0003
Title   :       Buffer Overrun in NAI WebShield SMTP v4.5.44 Management Tool
Author  :       DCIST (securityteam@delphisplc.com)
O/S     :       Microsoft Windows NT v4.0 Server (SP6)
Product :       NAI WebShield SMTP v4.5.44 / v4.5.74
Date    :       08/05/2000

I. Description

II. Solution

III. Disclaimer
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I. Description
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Delphis Consulting Internet Security Team (DCIST) discovered the following vuln-
erability in the NAI Management Agent for WebShield SMTP under Windows NT.

Firstly telneting to a machine which runs the management agent on port 9999 will
allow you to gain the current configuration by executing the command below.

GET_CONFIG<CR>

Secondly if you pass an oversized buffer of 208 bytes or more within one of the 
configuration parameters (there may be more) the service will crash overwriting 
the stack but and the EIP (208 + 4) with what ever was passed within the parameter.

SET_CONFIG<CR>
Quarantine_Path='Ax208'+ EIP

This enables an attack to execute arbitrary code on host server inheriting the 
permissions of account of which the service was running as.


II. Solution
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Vendor Contacted: 8-May-2000

Currently there is no vendor patch available but the following are preventative
measures Delphis Consulting Internet Security Team would advice users running
this service to implement.

o Don't allow the service to run as SYSTEM but as a restricted user account.
o Access list port 9999 on the local router or firewall to restrict access
to only required machines.
o Stop the management service.


III. Disclaimer
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THE INFORMATION CONTAINED IN THIS ADVISORY IS BELIEVED TO BE ACCURATE AT
THE TIME OF PRINTING, BUT NO REPRESENTATION OR WARRANTY IS GIVEN, EXPRESS OR
IMPLIED, AS TO ITS ACCURACY OR COMPLETENESS.  NEITHER THE AUTHOR NOR THE
PUBLISHER ACCEPTS ANY LIABILITY WHATSOEVER FOR ANY DIRECT, INDIRECT OR
CONSEQUENTIAL LOSS OR DAMAGE ARISING IN ANY WAY FROM ANY USE OF, OR RELIANCE
PLACED ON, THIS INFORMATION FOR ANY PURPOSE.
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