Yes, this is extremely common, and the oldest trick in the book. Make people think they have somehow lucked or won money, and then ask them for a fee before they can withdraw it.
You see it everywhere, Bitcoins, virtual items (think csgo, other ecash stuff), usually this is done through something like you posted, where the user thinks he has "stumbled" or "lucked" on a large sum of money, while in reality, it was infact all planted and or rigged.
You just stumbled upon a slight variation of this scam where they planted an SSH combo to a server that supposedly "hosts" a bitcoin wallet with 2.7BTC, but of course, before you can "withdraw" it, you need to deposit money first.
It's all the same scam.
If it's so common, why is there literally no posts anywhere on the internet about it? lol. It's pretty dam clever.
to say thank you
i'm a tech savvy person and never got into btc.
i somehow found these credentials. and the same prompt appeared. so i bought 0.01 btc and made a wallet. it is not transfered yet so i can get my money back.
at the moment i'm attempting to brute force their ubuntu os and dump their data and destory their stuff.
No problem, exactly why I posted this on here because there is basically no other information on the web about it. I'm glad you didn't fall for it and waste your .01 BTC