That doesn't look like an untouched shadow file (the root account should be locked, which is indicated by a simple bang character in the password field).
In any case, that should be irrelevant, the default config should let you in no matter what (over USB only, that goes out the window as soon as you enable the "SSH over WiFi" thingy in KUAL [or enable the use of the OpenSSH server instead of dropbear]).
Which would point to a PEBCAK in where you're actually trying to connect, which is what @knc1 is asking you to look into
.