Firewall Conformance Testing

Firewalls are widely used to protect networks from unauthorised access. To ensure that they implement an organisation’s security policy correctly, they need to be tested. We present an approach that addresses this problem. Namely, we show how an organisation’s network security policy can be formally specified in a high-level way, and how this specification can be used to automatically generate test cases to test a deployed system. In contrast to other firewall testing methodologies, such as penetration testing, our approach tests conformance to a specified policy. Our test cases are organisation-specific — i.e. they depend on the security requirements and on the network topology of an organisation — and can uncover errors both in the firewall products themselves and in their configuration.