it sounds like a trojan or other piece of malware. DNSChanger variants for OSX exist and might not have been affected by the FBI's efforts to shut down DNSChan

it sounds like a trojan or other piece of malware. DNSChanger variants for OSX exist and might not have been affected by the FBI's efforts to shut down DNSChanger itself, though it could just as easily be some other malware. It could even be something that infected your router, such things exist. http://it.slashdot.org/story/09/03/23/2257252/botnet-worm-targets-dsl-modems-and-routers http://it.slashdot.org/story/09/03/23/2257252/botnet-worm-ta... You shouldn't take this lightly, and definitely shouldn't bank online or otherwise do anything that should require any kind of security until you resolve this.