DOCUMENT:Q158724  19-MAR-1999  [iis]
TITLE   :HTTP 500 Server Error Unable to Perform a Security Operation
PRODUCT :Internet Information Server
PROD/VER:winnt:2.0,3.0,4.0
OPER/SYS:
KEYWORDS:kbenv

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The information in this article applies to:

 - Microsoft Internet Information Server versions 2.0, 3.0, 4.0 
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SYMPTOMS
========

In IIS 2.0 and 3.0, when you choose a link that references a file for download,
you may receive the following error message:

   HTTP/1.0 500 Server Error (Unable to perform a security operation on an
   object which has no associated security.)

In IIS 4.0, you will be challenged for credentials, with no credentials working,
and then receive a 403.1 Access Denied error.

CAUSE
=====

In a directory that has both Read and Execute permissions, when you attempt to
activate a link that references an executable file (such as in a self-
extracting .exe file), Internet Information Server attempts to execute rather
than download the file. If the file is a 32-bit program it will be executed,
however, if it is a 16-bit executable IIS generates the HTTP Server Error listed
in the Symptoms section of this article. This occurs because you cannot execute
16-bit CGI programs.

RESOLUTION
==========

Remove Execute permission on the virtual directory that the downloadable file is
mapped to and make sure that Read permission is allowed. For security reasons,
you should not grant Read and Execute permission at the same time on a virtual
directory. This configuration allows users to read script files that contain
proprietary information about settings which can compromise server security.

Additional query words: download IIS

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Keywords          : kbenv 
Technology        : kbiisSearch kbiis400 kbiis300 kbiis200
Version           : winnt:2.0,3.0,4.0
Issue type        : kbprb

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