• Oracle Transparent Network Substrate (TNS) server is a communication protocol that facilitates communication between Oracle databases and applications over networks.

Default Configuration

• Listener listens for incoming connections on the TCP/1521 port.
• Default port can be changed during installation or later in the configuration file.
• The configuration files for Oracle TNS are called tnsnames.ora and listener.ora and are typically located in the $ORACLE_HOME/network/admin directory.
• The tnsnames.ora file is used by Oracle databases to store connection details for different services. Each entry in the file includes a name for the service, the network location (address and port), and the database or service name. This helps clients easily connect to the correct database or service.

Tnsnames.ora

ORCL =
  (DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = TCP)(HOST = 10.129.11.102)(PORT = 1521))
    )
    (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = orcl)
    )
  )

Here we can see a service called ORCL, which is listening on port TCP/1521 on the IP address 10.129.11.102. Clients should use the service name orcl when connecting to the service.

Listener.ora

• Server-side configuration file that defines the listener process's properties and parameters, which is responsible for receiving incoming client requests and forwarding them to the appropriate Oracle database instance.

ID_LIST_LISTENER =
  (SID_LIST =
    (SID_DESC =
      (SID_NAME = PDB1)
      (ORACLE_HOME = C:\\oracle\\product\\19.0.0\\dbhome_1)
      (GLOBAL_DBNAME = PDB1)
      (SID_DIRECTORY_LIST =
        (SID_DIRECTORY =
          (DIRECTORY_TYPE = TNS_ADMIN)
          (DIRECTORY = C:\\oracle\\product\\19.0.0\\dbhome_1\\network\\admin)
        )
      )
    )
  )

LISTENER =
  (DESCRIPTION_LIST =
    (DESCRIPTION =
      (ADDRESS = (PROTOCOL = TCP)(HOST = orcl.inlanefreight.htb)(PORT = 1521))
      (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1521))
    )
  )

ADR_BASE_LISTENER = C:\\oracle

Nmap

• sudo nmap -p1521 -sV 10.10.10.10 --open
• sudo nmap -p1521 -sV 10.10.10.10 --open --script oracle-sid-brute - SID Bruteforcing

./sqlplus dbsnmp/dbsnmp@10.129.231.147/XE

ODAT