Googling the nickname we find some interesting stuff.
First of all his twitter account. Scrolling the post we find the car he love


Another interesting page is keybase!

In this page we can see his name. It's also a link to his 3 device, let's see:

Now that we know that he has a oneplus registered on 27 November we can try the oneplus models of that period.
In this case the 7pro was the right one.

# FLAG
X-MAS{t3sl@_cyb3rtruck_mihai_dancaescu_oneplus7pro}

Original writeup (https://github.com/Internaut401/CTF_Writeup/blob/master/2019/X-MAS%20CTF%202019/Dox%20the%20Yak.md).