Question on securiy in mock exam

Hi,

Following are the two question from the j2eecertificate.com on security

Question 1. Which of the following programs are classified as malicious code ( Check all the correct answers )

1. Virus,
2. Denial-of-service attack
3. IP spoofing
4. Trojan Horse
5. spamming

Answers given are 1 and 4. But I consider all the above are malicious in some way.

Question 2. What technique can be used to attack a web site.

1. IP spoofing
2. Encryptioh
3. spamming
4. secure socket layer
5. Obfuscation

Answers given are 1. Why not 3.

May I request to all ranchs who cleared this exam that is there such a question in exam. These question are comman to all technologies and not specific to Servlets and JSPs.

Thanks