A REST API Fuzz Testing Framework Based on GUI Interaction and Specification Completion

With the rapid development of Internet technology, REST APIs (Representational State Transfer Application Programming Interfaces) have become the primary communication standard in modern microservice architectures, raising increasing concerns about their security. Existing fuzz testing methods include random or dictionary-based input generation, which often fail to ensure both syntactic and semantic correctness, and OpenAPI-based approaches, which offer better accuracy but typically lack detailed descriptions of endpoints, parameters, or data formats. To address these issues, this paper proposes the APIDocX fuzz testing framework. It introduces a crawler tailored for dynamic web pages that automatically simulates user interactions to trigger APIs, capturing and extracting parameter information from communication packets. A multi-endpoint parameter adaptation method based on improved Jaccard similarity is then used to generalize these parameters to other potential API endpoints, filling in gaps in OpenAPI specifications. Experimental results demonstrate that the extracted parameters can be generalized with 79.61% accuracy. Fuzz testing using the enriched OpenAPI documents leads to improvements in test coverage, the number of valid test cases generated, and fault detection capabilities. This approach offers an effective enhancement to automated REST API security testing.