Through our security consultations, we have consistently identified poor Oracle Database Listener (TNS Listener) security as a significant security risk. Few Oracle database installations have properly secured the Oracle listener as recommended by Oracle and security experts.

The information contained in this paper is not new, is not obscure. It may not be well known to many Oracle DBAs, but is well known to security experts and hackers.

The paper will outline the vulnerabilities in the Oracle TNS Listener and provide recommendations for properly securing it. Providing minimal security for the Listener is simple and should be done for all Oracle installations – development, test and production.


The information is this document is based on Oracle8i and Oracle9i. The information should be valid for 7.3.x and 8.0.x, but has not been tested.

Download the paper in PDF format here.