RLOGIN(1): The Untold Story

Abstract : Coding defects account for a significant portion of the reports received by the CERT(registered) Coordination Center. Through in-depth analysis of these reports and generalizing our findings from those analyses, we have begun to create guidelines for mitigation strategies for existing defects and avoidance strategies when coding new software. In this document, we report the results of our analysis of the well known defect in the rlogin program. We discuss the coding defect in detail, three mitigation strategies devised to remedy the defect, and two avoidance strategies offered as a guide to reducing the instances of similar coding defects in new programs. We end with three design notes aimed at eliminating these defects at the hardware and protocol design level.