OpenSSH Vulnerability

Palo Alto Networks makes use of a the OpenSSH tool. CVE-2016-6210 was recently confirmed to be applicable to the version in use by PAN-OS. (Ref # 100977/CVE-2016-6210).
To exploit this vulnerability, an attacker would have to guess usernames defined as system administrators on the firewall.
This issue affects PAN-OS 5.0.X and earlier; PAN-OS 5.1.X and earlier; PAN-OS 6.0.14 and earlier; PAN-OS 6.1.14 and earlier; PAN-OS 7.0.10 and earlier; PAN-OS 7.1.5 and earlier

Work around:
Palo Alto Networks recommends following best practices by not relying on hidden usernames and setting unique, long, and complex passwords for each of the firewall users.