Security Advisory: Hassan Consulting's shop.cgi Directory Traversal Vulnerability.

[f0bic <f0bic () deadprotocol org>]

[ October 7, 2000 ]


Security Advisory (shop.cgi.ad-1.00-10) : Hassan Consulting's Shopping Cart (shop.cgi) Directory Traversal Vulnerability




Affected Product:

        * Hassan Consulting's Shopping Cart (shop.cgi/shop.pl) Version 1.18 (possibly others aswell)


Affected Platforms:

        * Unix
        * Windows


Overview:

        Hassan Consulting's Shopping Cart is one of the thousands of shopping scripts out there. It supports SSL, 
contains authentication
        modules for Cybercash, Authorize.net, and Linkpoint. The shop.cgi uses secure authentication through modules 
with's it's configuration
        file in shop.cfg.


Description:

        The regular syntax for displaying shopping information is: 
http://example.com/cgi-bin/shop.cgi/page=products.htm/SID=SHOPPING_ID_HERE .
        This will display a page called products.htm with the shopper's id (shoppers cart, information, etc.). The 
$page variable is displayed by
        calling an open() statement. This open statement doesn't perform any input/access validation and has no 
bounderied directories, therefore
        allowing http://example.com/cgi-bin/shop.cgi/page=../../../../etc/passwd to be passed in the open statement and 
/etc/passwd to be opened.
        The affected files are shop.cgi and shop.pl located in the cgi scripts directories (/cgi-bin, /cgi-local, 
/scripts, and the like).


Solution:

        By adding input validation using regex, you can single out characters such as ../ , .\./ . Also maybe a 
variable should be added that
        limits the dept of the directory traversal. These two combined can prevent arbitrary directory traversal from 
being performed by a
        possible attacker.




---------------------------------
by f0bic (f0bic () deadprotocol org)
zSh - http://zsh.interniq.org