Recent trends in the software development practices (Agile, DevOps, CI) have shortened the development life-cycle causing the need for efficient security-by-design approaches. In this context, software architectures are analyzed for potential vulnerabilities and design flaws. Yet, design flaws are often documented with natural language and require a manual analysis, which is inefficient. Besides low-level vulnerability databases (e.g., CWE, CAPEC) there is little systematized knowledge on security design flaws. The purpose of this work is to provide a catalog of security design flaws and to empirically evaluate the inspection guidelines for detecting security design flaws. To this aim, we present a catalog of 19 security design flaws and conduct empirical studies with master and doctoral students. This paper contributes with: (i) a catalog of security design flaws, (ii) an empirical evaluation of the inspection guidelines with master students, and (iii) a replicated evaluation with doctoral students. We also account for the shortcomings of the inspection guidelines and make suggestions for their improvement with respect to the generalization of guidelines, catalog re-organization, and format of documentation. We record similar precision, recall, and productivity in both empirical studies and discuss the potential for automating the security design flaw detection.