Security Analysis of FileZilla Server Using Threat Models

FTP is a widely used protocol for working with remote file systems. Various FTP implementations have had security problems reported as late as 2010. There lacks a systematic analysis of FTP security. In this paper, threat models are built to provide a systematic coverage of potential security attacks against an FTP server. Security tests are then generated from the threat models and applied to FileZilla Server, a popular FTP server implementation. When FileZilla Server is properly deployed, it holds fast against our security attacks. To further evaluate the effectiveness, the security tests are used to exercise a number of security mutants of FileZilla Server where various vulnerabilities are injected deliberately. The security tests have detected all but one of the injected vulnerabilities. This indicates that the threat model-based approach to security analysis of FileZilla Server is effective. KeywordsSecurity testing, FTP, threat modeling, threat tree, mutation testing