I'd be worried about legal repercussions if we were talking about the latest Disney movie, but this is merely the private information of a billion people. Never seen IP law give much of a crap about that before.
A collection of facts is not and can not be copyrightable, especially when it was mechanically derived/collected (no human creativity). So, no, it is absolutely not "Equifax's IP".
Not on an individual basis. If you collected a large number of them and someone copied them from you, then you could have a database right claim, which is sort of similar to copyright, but much less powerful. https://en.wikipedia.org/wiki/Database_right
3,000,000,000 leaked Social Security Numbers is a statistic.
-Joseph "Social Credit" Stalin
...Is it obvious I, as an American who can confirm my SSN (and whatever else) was leaked by this, sincerely couldn't care less because this is leak incident number 897165176548795647564576415671?
That $10 UberEats gift card from CrowdStrike would be more valuable than another batch of Free Credit Monitoring(tm).