Oracle Transparent Network Substrate(TNS)
Comm protocol that facilitates communication between Oracle DB and other apps on network.
Preferred solution to manage large DBs, in healthcare, finance, retail…
Default port: TCP/1521
Supports various protocols: TCP/IP, UDP, IPX/SPX, AppleTalk
Can be remotely managed in Oracle 8i/9i, not in Oracle 10g/11g
By default: Hosts whitelist only, basic auth using hostname, IP, username, password
Conf files: tnsnames.ora, listener.ora, usually in $ORACLE_HOME/network/admin.
Often used with Oracle DBSNMP, Oracle DB, Oracle App Server, Oracle Enterprise Server, Oracle Enterprise Manager, Oracle Fusion Middleware, web servers, etc..
Many evolutions: Oracle 9 has a default password: CHANGE_ON_INSTALL, but Oracle 10 has no default password
Oracle DBSNMP has default password: dbsnmp
Many orgs use the finger service with Oracle, which makes it vulnerable when we have the required knowledge of a home directory.
Each DB or service has a unique entry in the tnsnames.ora file.