This project describes the design and implementation of protocol scrubbers. Protocol scrubbers are transparent, interposed mechanisms for explicitly removing network scans and attacks at various protocol layers. The transport scrubber supports downstream passive network-based intrusion detection systems by converting ambiguous network flows into well-behaved flows that are unequivocally interpreted by all downstream endpoints. The fingerprint scrubber restricts an attacker's ability to determine the operating system of a protected host. As an example, this paper presents the implementation of a TCP scrubber that eliminates insertion and evasion attacks--attacks that use ambiguities to subvert detection--on passive network-based intrusion detection systems, while preserving high performance. The TCP scrubber is based on a novel, simplified state machine that performs in a fast and scalable manner. The fingerprint scrubber is built upon the TCP scrubber and removes additional ambiguities from flows that can reveal implementation-specific details about a host's operating system.

TITLE PAGE

CERTIFICATION

DEDICATION

ACKNOWLEDGEMENT

ABSTRACT

TABLE OF CONTENTS 

CHAPTER ONE

INTRODUCTION

CHAPTER TWO

CHAPTER THREE

METHODOLOGY FOR FACT FINDING AND DETAILED DISCUSSION OF THE SUBJECT MATTER

CHAPTER FOUR

THE FUTURE, IMPLICATIONS AND CHALLENGES OF THE SUBJECT MATTER FOR THE SOCIETY

CHAPTER FIVE

SUMMARY, RECOMMENDATION AND CONCLUSION

REFERENCES