Computer Security: Art and Science

Chapter 22. Malicious Logic

	TITUS ANDRONICUS: Ah!, wherefore dost thou urge the name of hands?To bid Aeneas tell the tale twice o'er,How Troy was burnt and he made miserable?
	--The Tragedy of Titus Andronicus, III, ii, 26–28.

Computer viruses, worms, and Trojan horses are effective tools with which to attack computer systems. They assume an authorized user's identity. This makes most traditional access controls useless. This chapter presents several types of malicious logic, focusing on Trojan horses and computer viruses, and discusses defenses.

Introduction

Odysseus, of Trojan War fame, found the most effective way to breach a hitherto-impregnable fortress was to have people inside bring him in without knowing they were doing so [482, 1016]. The ...