This is hardly new, but I agree it is an issue. The answer to this security issue is either: 1) The bit.ly route - store off-site urls your organization wants

This is hardly new, but I agree it is an issue. The answer to this security issue is either: 1) The bit.ly route - store off-site urls your organization wants to link to as a value and give the user an url with just the key in it. 2) Create a secret salted hash of the url and include that with the url in the args. Upon request, the receiver would re-hash the url and compare it to the hash given. Unless someone reverse engineered your hash this system prevents someone casually manipulating a url.