If you use any Microsoft cloud product that includes AD FS for single-login authentication, read this item, in its entirety! Now! This item describes yet another reason to use open source products, and avoid the closed-source alternatives.
That’s a terrible thing, but not surprising. Those miscreants will stoop low enough, and do anything to get your/our money, but bad on that insurance fund too. They should have known to secure their member’s data better than they did, by at least encrypting it so even if they get hacked, the crackers won’t be able to read anything they get. I know encryption isn’t a perfect solution, but it’ll sure make life harder for the bad guys.