11.2 Spam

Question 1

Spam definition

Answer 1

Unwanted commercial email

Question 2

Most spam ends up in your spam folder. T/F

Answer 2

T

Question 3

Problem with spam

Answer 3

1. Filters: have to separate good from bad
2. Storage
3. Security problems

Question 4

Filter

Answer 4

prevent message from reaching inbox

Question 5

Filer problem: How to differentiate spam from “ham”

Answer 5

1. Content based
2. IP address of sender (blacklisting)
3. Behavior features (how the mail is sent)

Question 6

BGP “Agility” Surprise

Answer 6

1. Hijack IP prefix
2. send spam
3. withdraw

makes ip blacklists useless

Question 7

Things determinable from a single-packet receiver

Answer 7

distance between sender and receiver
Density
Local time of day
AS of senders IP

Question 8

Things determinable from a single-message

Answer 8

# of recipients
length of message

Question 9

Things determinable from aggregates

Answer 9

variation in message length

Question 10

SNARE

Answer 10

70% detection rate
0.1% false positive rate
uses network level features