Another ISAPI filter : deny user authentication through IIS to users you want.

From: Bob at firstcodings (bobat_private)
Date: Tue Mar 05 2002 - 15:55:24 PST

  • Next message: Dragos Ruiu: "cansecwest/core02"

     Hi members,
    
    I wrote an ISAPI filter that _deny_ user authentication through IIS even if
    NTFS permissions and user rights are _granted_.
    
    
    The facts :
    * "Basic authentication" is widely used by IIS on Internet (IIS 4 and 5)
    * NTFS permissions and user rights are granted to administrators (and other
    users that never connect through Internet) in 95% of the time
    
    The problem :
    A simple brute force attack to such servers may retreive administrator
    password which can be used in another exploit.
    
    The solution :
    For such users, authentication through IIS __must be denied__ even if __NTFS
    permissions and user rights are granted__.
    
    
    I wrote an ISAPI filter that do this job (not only for "administrator"
    user); the page can be found at
    http://bob.firstcodings.com/programs/authentprotect/ (source code is
    included). For now, please consider this filter as "beta release", so use it
    at your own risk !
    
    Email me at "authentProtectat_private" for any
    comments/feedbacks/suggestions about this filter.
    
    
    Bob - firstcodings.
    



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