KPMG-2002004: Lotus Domino Webserver DOS-device Denial of Service

[Peter Gründl <pgrundl () kpmg dk>]

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      -=>Lotus Domino Webserver DOS-device Denial of Service<=-
                      courtesy of KMPG Denmark

BUG-ID: 2002004          Released: 4th Feb 2002
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Problem:
========
The Domino Webserver does not handle URL request for DoS-Devices
correctly. This vulnerability can be exploited by a malicious user
to bring down the webserver.

Vulnerable:
===========
- Lotus Domino Webserver prior to 5.0.9a on Windows 2000

Details:
========
there are two issues in the Domino Webserver that give similar
results when exploited.

First issue)
A request for a DOS-device from CGI-BIN with any given extension
is accepted by the server as a valid request and is passed on
the to cgihandler (nhttpcgi.exe). Due to the nature of DOS-
devices (CON, AUX, PRN etc.) the process never releases the file
again, and when Domino's limit of 400 working threads has been
reached, the server will no longer accept requests.

Second issue)
Requesting a DOS-device (eg. NUL) from CGI-BIN with an extension
of 220 chars (eg. 220x"a") results in the server spawning
cmd.exe to run, in this case, nul.pif. The server will then pop
up a window, asking which file you want to open nul.pif with.
This can be done 400 times, before the server runs out of
working threads or less, if it runs out of memory, since this
attack opens up a lot of processes.

Vendor URL:
===========
You can visit the vendors webpage here: http://www.lotus.com

Vendor response:
================
The vendor was contacted on the 1st of November, 2001. On the 5th
of November the vendor confirms that they have reproduced the issues
on Windows 2000. The issues were assigned bug id: JCHN4UMKLA and
JCHN547JWV by the vendor. On the 4th of January, 2002, it was
confirmed that the patch corrected the two issues mentioned in this
advisory.

Corrective action:
==================
Upgrade to Domino 5.0.9a, which can be downloaded here:
http://notes.net/qmrdown.nsf


   Author: Peter Gründl (pgrundl () kpmg dk)

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