Referer spoofing

In computer security, referer spoofing or ref tar spoofing is the sending of incorrect referer information along with an HTTP request, sometimes with the aim of gaining unauthorized access to a web site. It can also be used because of privacy concerns, as an alternative to sending no referer at all.

Application

Some subscription sites, especially many pornographic paysites, utilize referer information to secure their materials: only browsers arriving from a small set of approved (login-) pages are given access; this facilitates the sharing of materials among a group of cooperating paysites.If attackers acquire knowledge of these approved referers (which is often trivial because many sites follow a common template), they can then gain free access to the materials.

Spoofing often allows legitimate access to a site's content where the site's web server is configured to block browsers not sending referer headers. Web site owners may do this to disallow hotlinking.

It can be also used to defeat referer checking controls that are used to mitigate Cross-Site Request Forgery attacks.

Tools

Several software tools exist to facilitate referer spoofing:
* Proxomitron is a proxy capable of referer spoofing.
* The Mozilla Firefox extension refspoof [http://refspoof.mozdev.org/] allows to use a custom referer URL for any site one visits, and provides a mechanism to manage a bookmark list of such referer/site pairs.
* QuickSpoof and Spooph provide the same functionality for the Internet Explorer browser.
* SuperMegaSpoof [http://www.supermegaspoof.com/] is a Windows application that supports both browsers and allows users to exchange and rate referer spoofs; it displays advertisements while it is running.

See also

* Referer spam