# What is Computer Systems Security?

## Lecture

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What is Computer Systems Security?
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## Hacking Methodology

**Steps:**

1. Reconnaissance
2. Gaining a foothold
3. Internal reconnaissance
4. Gaining influence in the network
5. Total compromise
6. gLoAtInG

## Computer Systems (In)Security

* Modern computer systems are **complex**. With great complexity comes great vulnerability.
* There is an attack/defense asymmetry:
  * A chain is only as strong as its **weakest link**.
  * To win, the defender has to block **every attack**.
  * To win, the attacker has to succeed **just once**.
* Even good defenses fail!

## Ethics

* **Don't do anything illegal!**
  * NEVER EVER EVER EVER EVER hack into a system that you do not have explicit **permission** to hack.
  * Never attempt to find vulnerabilities in a system that you do not own or have **permission** to audit.
