Firewall Testing Policy-Based Test Case Generation
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Solution Overview
Problem
Current firewall testing methods are inefficient and impractical due to the need for specialized knowledge, long execution times, and failure to account for domain heuristics, leading to incomplete error detection in firewall configurations and implementations.
Innovation Solution
A method that allows non-specialized administrators to create a high-level policy model of a firewall, transforming it into a formal specification for generating test cases, which are then used to detect errors in firewall implementations and configurations with high probability using a user-friendly interface and efficient test packet generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If exhaustive testing is performed against every possible packet header, then complete verification of firewall correctness is achieved, but the testing time and computational resources become prohibitively long and impractical
Solution Approach 1:
The patent applies partial action by selecting a representative subset of test packets that cover critical firewall behaviors and policies, rather than testing every possible packet header. This approach uses policy-based test generation to identify and execute only the most relevant test cases, achieving sufficient verification without exhaustive coverage of all possible inputs.
Solution Approach 2:
The patent transforms the testing approach by changing parameters from exhaustive packet header variations to policy-driven test case selection. By using formal policy specifications to guide test generation, the system focuses on parameters that matter most for firewall correctness, reducing the test space from all possible packets to a manageable subset that still provides high verification confidence.
2Extent of automation
If model-based testing is performed using existing systems like HOL-TestGenFW, then systematic test case generation is achieved, but the execution time becomes prohibitively long and specialized knowledge is required
Solution Approach 1:
The patent extracts and separates the policy specification component from the test generation process. By allowing administrators to define policies in a simplified, domain-specific language rather than requiring full formal method expertise, the system removes the barrier of specialized knowledge while maintaining automated test generation capabilities.
Solution Approach 2:
The patent introduces a policy specification layer as an intermediary between administrator intent and formal test case generation. This intermediary layer uses a simplified policy language that administrators can understand and manipulate, which then gets automatically translated into formal test cases, bridging the gap between user capability and systematic testing requirements.
3Extent of automation
If existing model-based testing systems are used, then test case generation is systematic, but they lack domain heuristics and fail to detect common error sources effectively
Solution Approach 1:
The patent applies preliminary action by incorporating domain heuristics and common error patterns into the test generation process upfront. By analyzing historical firewall configuration errors and domain-specific knowledge, the system pre-configures test priorities and focuses on areas where errors are most likely to occur, enhancing error detection capability before testing begins.
Solution Approach 2:
The patent implements feedback mechanisms that use domain heuristics to guide and adjust test case generation. By incorporating knowledge about common firewall misconfigurations and error patterns, the system can prioritize test cases that are most likely to reveal actual problems, improving the effectiveness of error detection while maintaining systematic generation.
Data Source
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AI summary
The invention provides a method of testing a firewall for a communications network, and an equivalent apparatus. More specifically, the method allows a high-level firewall policy model to be defined based on input provided by a firewall administrator without specialised knowledge in mathematically formal languages. The firewall policy model represents an idealisation of the firewall under test, the firewall policy, and the network environment in which the firewall is deployed. One or more sets of test cases is generated based on the policy mode. The generated test case set includes at least one test case comprising a specification of a packet to be processed by the firewall under test and the expected outcome of processing the packet by a firewall compliant with the policy. Preferably, the generated test case set allows potential failure of the firewall under test to implement the policy correctly to be detected. The test packets specified in the test cases are subsequently provided to the firewall under test for processing. The outcome of the processing is monitored, and the observed packets compared with the expected results to determine whether the firewall under test is functioning according to the firewall policy.