11.2 - Spam

Question 1

Spam

Answer 1

Most spam ends up in your spam folder

Problem:

1. Filters: separate good from bad
2. Storage
3. Security problems (e.g., phishing)

Question 2

Filter

Answer 2

Prevent message from reaching inbox

Question 3

3 different ways to construct filters

Answer 3

1. Content-based -> easy to evade
2. IP address of sender (blacklist) ->
3. Behavioral features -> filter based on how message is sent
   
   • Geographic location of sender/receiver
   • Set of target recipients
   • Upstream ISP
   • Botnet

Challenges of building a filter around behavioral feature:

1. Understanding
2. Building classifiers

Question 4

Problems w/content-based filters?

Answer 4

easy for attackers to evade