Quick temporary fix for OWA DOS

From: Martin Dion (martin.dionat_private)
Date: Sat Aug 25 2001 - 08:10:58 PDT

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    Good morning all,
    
    For people who have this issue within there servers, we have a found a
    temporary fix, it can permanent if you wish but it put more user
    administration in the loop.
    
    Configure IIS to Challenge-Response the access on the login page, that way,
    non legitimated users that tries to cause the DOS in your OWA won't have
    access to the component that cause that problem.
    
    Simple and effective.
    
    Have a good week end.
    
    Martin Dion
    Vice-President
    Technology and Security Services
    
    Above Technology
    Phone: (450) 430-8166
    Cell: (514) 831-5427
    Email: martin.dionat_private <mailto:martin.dionat_private>
    
    
    
    -----Message d'origine-----
    De : Andrew McQueen [mailto:amcqueenat_private]
    Envoyé : Wednesday, August 22, 2001 6:22 PM
    À : 'bugtraqat_private'
    Objet : OWA over ssl shutting down IIS
    
    
    Here is a copy of postings I posted to the iis security forum
    
    I have just found this bug with our IIS 4 server and OWA
    The server is SP6a with the hotfix roll up applied and also the 128 bit
    ssl upgrade OWA is running accross 128 bit ssl
    
    I log onto OWA with an extra long user name of % characters ie %%%%%%%%%
    (at least 30 times)
    I then receive the NT username and password box if I then fill both of
    these with the same characters and hit return till the page times out.
    
    The result ends up with world wide web publishing service is stopped
    And IIS admin service stopped
    
    
    exchange 5.5 sp4
    The iis server is separate to the exchange server
    I will be able give more specific info tommorrow!
    ie event logs, specific service packs etc
    I have replicated this problem 5 times now and not once has it failed to
    work.
    Is this a known problem and if not could it be exploited (apart from DOS)
    
    Andy Mcqueen (sorry about the footer it is a legal firm and is compulsory)
    



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