[derobert]

It is linked from the banner up top of https://www.equifax.com/personal/

"Equifax Cybersecurity Incident: To learn more about the cybersecurity incident, including whether your personal information was potentially impacted, or to sign up for complimentary identity theft protection and credit file monitoring, click here"

and that "click here" goes to http://www.equifaxsecurity2017.com/

So it'd seem legit, if rather silly to have its own domain.