Well, it is (highly) illegal for them to do this. So they presumably lie about everything, like name, location, ...
Perhaps fake is not the correct word, but the actual individuals are likely to have more than a few faked details. They do exist, of course.
It's also very dubious becuase, well, would you really hire a worker from an organization that also does things like hack hospitals and then hold systems hostage for bitcoin?
To be fair, "illegal" here doesn't matter. North Korea doesn't follow American law.
Obviously, when working you have to follow the law both in the country where you live and the country where you work. Even in the case of remote work. Sadly, even if you just consult. So you can be pretty sure: highly illegal.
Weird take on legality. They're working American jobs, breaking American law. Yes it matters.
I'm sure American law enforcement will get the chance to arrest them next time they set foot in the US. Or maybe DPKR will extradite them, who knows?
If we could prosecute and incarcerate them, how likely is it that a US prison is still an improvement over living in North Korea?