I've been addressing an open-redirect issue and in experimenting with the latest fix, I noticed that updating the redirect's protocol to file resulted in a blank page on the browser.
redirect.aspx?url=file://legitimate-site.com results in a blank page. Other protocols like
madeup:// get the error page suggesting there is a generic URL processor that says "these protocols are okay" and the browser or the proxy is blocking the malicious redirect.
Obviously, I want the team to limit redirection to just "http" and "https" but I'm curious as to if there are any browsers that perform redirects to local files or if this is a security hole that has been closed for a while. A quick search has yielded just a few "doesn't work" answers but nothing official.