It all depends on the implementation though, right? If Safari just does a simple check to see if the source URL is something like http://adserver.apple.com htt

It all depends on the implementation though, right? If Safari just does a simple check to see if the source URL is something like http://adserver.apple.com http://adserver.apple.com then it would be trivial to hack DNS and send WebGL to your iOS device. I can definitely see this being an attack vector used by jailbreakers to jailbreak iOS 5. I think the only way they could prevent these type of DNS jacking attacks is to use a trusted SSL certificate on their iAd servers. I'm not sure what type of performance penalty that would add, forcing all advertising traffic to use SSL.