mac os - virtualbox - oracle connection error - invalid username/password; logon denied
You can manual check password for HR (if You want - force SET it oracle)
Firewall is not important moment, because Oracle return You exactly error text

if all correct, it must be:

macbookva:instantclient_11_2 vladimir$ sqlplus HR/oracle@XE

SQL*Plus: Release 11.2.0.4.0 Production on Wed Nov 18 19:24:20 2015

Copyright (c) 1982, 2013, Oracle.  All rights reserved.


Connected to:
Oracle Database 11g Express Edition Release 11.2.0.2.0 - 64bit Production

SQL&gt;