Mitigating Access Control Vulnerabilities through Interactive Static Analysis

Abstract

Access control vulnerabilities due to programming errors have consistently ranked amongst top software vulnerabilities. Previous research efforts have concentrated on using automatic program analysis techniques to detect access control vulnerabilities in applications. We report a comparative study of six open source PHP applications, and find that implicit assumptions of previous research techniques can significantly limit their effectiveness. We propose a more effective hybrid approach to mitigate access control vulnerabilities. Developers are reminded in-situ of potential access control vulnerabilities, where self-review of code can help them discover mistakes. Additionally, developers are prompted for application-specific access control knowledge, providing samples of code that could be thought of as static analysis by example. These examples are turned into code patterns that can be used in performing static analysis to detect additional access control vulnerabilities and alert the developer to take corrective actions. Our evaluation of six open source applications detected 20 zero-day access control vulnerabilities in addition to finding all access control vulnerabilities detected in previous works.