Hi Ak2991,
Adware, browser hijackers, and potentially unwanted programs are these days able to infect the Apple Mac OS operating system. There is also a Zeus virus alert hoax that affects iOS that can hijack Safari and other browsers. This hoax isn't truly a Zeus virus, but an aggressive browser extension that redirects Safari, Chrome, or Firefox to a fake warning website.
We suggest that you scan and clean your devices with Malwarebytes Anti-Malware for Mac. Adware Medic is another tool designed to remove adware and browser hijackers from Apple Mac OS X.