I received 3 sms from this phone number within the last 12 hours. Each sms had the purpose to give me a (always different) security code for a Microsoft account, which I never asked for.

i got the text message from this number informing me "Someone else might have accessed Microsoft account(email address) Recover at http://account.live.com

Got a text message from 1 774 367 1456   Message said  Wait is over and security info for *******@live.ca was replaced.  Review at https://account.live.com/p                I never asked for security info to be replaced.

Ok, so I just checked my email at live.ca and I did get a message from Microsoft.  I had updated my security info and had added my cell phone number, but I had to wait for 30 days for it to be updated ( which I had forgotten about ).  The email reminded me that the 30 day wait was over and that my cell number had been added.  So I guess its a legit thing.

The reply wasn't to Amy, it was supposed to be an add on to my own message...sorry for confusion.