source: http://www.securityfocus.com/bid/4356/info

DCShop Beta is a freely available shopping cart system, written in Perl. It will run on most Unix and Linux variants, as well as Microsoft Windows operating systems.

It is possible to overwrite setup files (*.setup) by submitting attacker-supplied form data followed by a null character (%00). The attacker must use the POST method to submit data that is content-type multipart/form-data compliant. 

curl -F database=@test.txt http://host/cgi-bin/dcshop.cgi

where test.txt contains databasename.setup[nullbyte].