Microservices architecture has become the industry standard for developing and delivering cloud-based applications. These microservices communicate with each other using application programming interfaces (APIs), which serve as the backbone of the entire service platform. Such API architecture provides a platform for message and data transfer among distributed systems, microservices, and cloud-native applications. Most of the industry follows the REST (Representational State Transfer) architecture style to build and provide application services. APIs transport sensitive data, and any unsafe configurations and installations pose security threats to sensitive information. Thus, a systematic review of articles from the past 10 years is undertaken to identify the complex attack vectors and interdependencies that pose security risks to RESTful APIs. The review reveals a focus on testing, fuzzing, and scanning RESTful APIs to detect errors, bugs, faults, and security vulnerabilities. Furthermore, we concentrated on determining the roles of improved input generation and sequence-to-sequence modelling in increasing the security of RESTful APIs. Finally, the existing criteria for assessing security impacts in RESTful APIs and prevailing practices for robust security are identified, along with open challenges that need further study.

RESTful API, Complex attack vectors, Interdependencies, Enhanced input generation, Sequence-to-sequence modeling, Security, and Mitigation mechanisms