Zillow foreclosures not on MLS

I am an agent in Oregon only because I am a multi-family investor. However after being burned once in the past I am preparing to attempt another flip. After scouring the MLS I am not excited about many of the homes but on zillow they have some places listed under foreclosure that look pretty interesting. But then they send you to a foreclosure website that you have to pay for. I am just curious if anyone knows if this is legit. How does the process to buy these properties work?

Thank you for any insight,