Just today, my website started exhibiting strange behavior - whenever a user clicks on any link, they're navigated to the appropriate page on my site, but also a new tab opens to a spam site in their browser. I suspect malicious code was injected somewhere, but I'm not sure what to look for or where this might be. It must somehow be implemented globally because this is an issue with every link. I've seen instances where the user is simply redirected to a spam site - but never a new tab opening like this. Weird stuff.
Any help would be awesome!