Answers and Explanations

1. A. A botnet is a group of compromised computers, usually working together, with malware that was installed by a worm or a Trojan horse.

2. A and D. Host-based intrusion detection systems (HIDS) run within the operating system of a computer. Because of this, they can slow a computer’s performance. Most HIDS do not detect network attacks well (if at all). However, a HIDS can detect operating system attack and will usually have a high level of detection for those attacks.

3. C. Zombies (also known as zombie computers) are systems that have been compromised without the knowledge of the owner. A prerequisite is the computer must be connected to the Internet so that the hacker or malicious attack can make its way to the computer and be controlled remotely. Multiple zombies working in concert often form a botnet. See the section “