Security Engineering, 3rd Edition

CHAPTER 2Who Is the Opponent?

Going all the way back to early time-sharing systems we systems people regarded the users, and any code they wrote, as the mortal enemies of us and each other. We were like the police force in a violent slum.

– ROGER NEEDHAM

False face must hide what the false heart doth know.

– MACBETH

2.1 Introduction

Ideologues may deal with the world as they would wish it to be, but engineers deal with the world as it is. If you're going to defend systems against attack, you first need to know who your enemies are.

In the early days of computing, we mostly didn't have real enemies; while banks and the military had to protect their systems, most other people didn't really bother. The first computer systems were isolated, serving a single company or university. Students might try to hack the system to get more resources and sysadmins would try to stop them, but it was mostly a game. When dial-up connections started to appear, pranksters occasionally guessed passwords and left joke messages, as they'd done at university. The early Internet was a friendly place, inhabited by academics, engineers at tech companies, and a few hobbyists. We knew that malware was possible but almost nobody took it seriously until the late 1980s when PC viruses appeared, followed by the Internet worm in 1988. (Even that was a student experiment that escaped from the lab; I tell the story in section 21.3.2.)

Things changed once everyone started to get online. The mid-1990s saw ...