Hi ZUK Z2 owners,
I bought ZUK Z2 from aliexpress and mine came with stock rom (unopened box). I have updated the firmware to the latest (2.1.059 ST) using flyvpn.
I ran malwarebytes and found liulangbao malware. I have followed zuktastic's post from zukfans (http://zukfans.eu/community/threads/liulangbao.304/) and got rid of it.
You have to unlock, install twrp and root to get rid of this trojan.
I am not sure that App is built by ZUC.
Xiaomi has been having similar problems.
And it turned out that phone shops were buying Xiaomi phones to resell them overseas.
And before they did they would flash a different rom, and they would put malware in those roms.
The shops themselves don't own the malware, they were just getting paid by other companies to put it there.
I guess this means root/unlocked bootloader/sources/documentation is even more important when it comes to grey imports.