KPMG-2002003: Bea Weblogic DOS-device Denial of Service

[Peter Gründl <pgrundl () kpmg dk>]

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           -=>Bea Weblogic DOS-device Denial of Service<=-
                      courtesy of KMPG Denmark

BUG-ID: 2002003          Released: 8th Jan 2002
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Problem:
========
A flaw in the way the Bea Weblogic server handles specific requests
containing DOS-devices can cause a Denial of Service situation,
where web requests are no longer being serviced.

Vulnerable:
===========
- Bea Weblogic Server 6.1 Service Pack 1 for Windows NT/2000
- Older releases and other pure java application servers could be
  vulnerable, but haven't been tested.

Details:
========
When the Weblogic server receives a .jsp request, it invokes an
external compiler to deal with the .jsp ressource requested. The
server can be fooled into thinking you are requesting a valid .jsp
ressource by simply requesting a DOS-device (such as eg. aux) and
appending the .jsp extension to it (aux.jsp). The external compiler
is then invoked and due to the nature of the DOS-devices, this
working thread never finishes.

The server can handle about a 10-11 working threads, so when this
number of active threads has been reached, the server will no
longer service any requests. Since both HTTP and HTTPS are handled
by the same module, both are crippled if one is attacked.

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

Vendor response:
================
The vendor was contacted on the 6th of November, 2001. On the 15th
of November the vendor confirms that they have reproduced the issue
on Windows 2000 and Windows NT. The issue is assigned the bug id:
CR062542 by the vendor. On the 3rd of January, 2002 the vendor
confirmed the release of the new service pack and that it included
the patch for this issue.

Corrective action:
==================
Upgrade to Service Pack 2, which can be downloaded here:
http://commerce.beasys.com


   Author: Peter Gründl (pgrundl () kpmg dk)

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