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Vulnerability Assessment Details
Acertains the presence of showcode.asp
Detailed Explanation for this Vulnerability Assessment
Internet Information Server (IIS) 4.0 ships with a set of sample files to
help web developers learn about Active Server Pages (ASP). One of these
sample files, 'showcode.asp' (installed in /msadc/Samples/SELECTOR/), is
designed to view the source code of the sample applications via a web
The 'showcode.asp' file does inadequate security checking and permits anyone
with a web browser to view the contents of any text file on the web server.
This includes files that are outside of the document root of the web server.
The 'showcode.asp' file is installed by default at the URL:
It takes 1 argument in the URL, which is the file to view.
The format of this argument is: source=/path/filename
This is a fairly dangerous sample file since it can view the contents of any
other files on the system. The author of the ASP file added a security check to
only permit viewing of the sample files which were in the '/msadc' directory on
the system. The problem is the security check does not test for the '..'
characters within the URL. The only checking done is if the URL contains the
string '/msadc/'. This permits URLs to be created that view, not only files
outside of the samples directory, but files anywhere on the entire file
system that the web server's document root is on.
The full description can be found at: http://www.l0pht.com/advisories.html
Solution : For production servers, sample files should never be installed, so
delete the entire /msadc/samples directory. If you must have the
'showcode.asp' capability on a development server, the 'showcode.asp' file
should be modified to test for URLs with '..' in them and deny those requests.
Network Security Threat Level: High
Networks Security ID: 167
Vulnerability Assessment Copyright: This script is Copyright (C) 1999 Immo Goltz
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