Open redirect URLs: Is your site being abused?

Saturday, January 31, 2009

No one wants malware or spammy URLs inserted onto their domain, which is why we all try to follow good security practices. But what if there were a way for spammers to take advantage of your site, without ever setting a virtual foot in your server? There is, by abusing open redirect URLs.

Webmasters face a number of situations where it's helpful to redirect users to another page. Unfortunately, redirects left open to any arbitrary destination can be abused. This is a particularly onerous form of abuse because it takes advantage of your site's functionality rather than exploiting a simple bug or security flaw. Spammers hope to use your domain as a temporary "landing page" to trick email users, searchers and search engines into following links which appear to be pointing to your site, but actually redirect to their spammy site.

We at Google are working hard to keep the abused URLs out of our in