Explain the challenges of reading /etc/passwd and /etc/shadow
The B10B has an autogenerated supervisor password (hashed from the serial number). Earlier models left a md5crypt type hash in /etc/passwd, however firmware AAVF.10 changed to a SHA-512 type hash stored in /etc/shadow.
<strike>You may have some success reading this file by logging into the router as the "admin" user via SSH. </strike> You would need to crack the hash (e.g. with hashcat), the password will be 8 characters long using characters 0-9,a-f (lower case)