Izito and similar sites keep appearing on my search engine results. It started a few weeks ago. It has been happening on both - my Ubuntu and Windows computer, and even on a new Windows computer. It has been happening on Chrome and Microsoft Edge and on Google and Bing. I have since installed Bitdefender AV and done factory resets and it still keeps coming back after a while. I was wondering if someone could please advise on what might be causing it, what damage / impact it might (have) caused, and how I could get rid of it.
If you're sure the search results are NOT advertisement, then they might be redirecting your searches to their servers by redirecting. Normally they do these through installing browser plugins (via bundling with free software etc.). But you're saying this happens on a brand new installation which suggests network level rerouting or root kit (unlikely)
Process of elimination:
Before doing anything, just try using a live Linux (booted from CD or flash drive) for a while and see if the problem happens again. Don't install any of your usual software, just use browser. If it does happen again, your routers/wi-fi device (or your ISP) is a suspect. Try again on a different network (try a public wi-fi for example). If that solves the problem, you know it's in your network. If it still does happen on another network (very unlikely), then there could be a firmware level infection (again very unlikely - try with another laptop then).
If you figure out the problem is only within your network, try setting your DNS manually (instead of using your ISP's DNS automatically) on that live Linux. You can use CloudFlare's free DNS service 126.96.36.199. If that solves the problem, then the problem is with your router/wi-fi devices (infected to reroute requests) or its your ISP (very unlikely - but if it is an extremely cheap service - maybe).
Try hard resetting your router & wi-fi and then update their firmware. Review their settings (enable firewall for example). If they are too old, consider replacing them. Routers are getting targeted in last few years b/c they are easy targets. They could be hijacking DNS settings or randomly serving different content on your requests.