Computer Security Questions and Answers

Answer: B

Correct answer: The CD–ROM stops functioning

A drive that stops working is a hardware fault; nothing in a virus's usual repertoire disables the mechanism. The other three - files and icons vanishing, the browser's home page changed, strange messages on screen - are all things software can do and all classic signs of infection.

Answer: B

Correct answer: Zombie

A zombie is a machine that has been taken over and is used, together with thousands of others, to flood a target with traffic. The collection of them is a botnet, and the flood is the denial of service. A worm may be the means of recruiting them, but the attack itself is launched by the zombies.

Answer: D

Correct answer: Trojan horses

A trojan is defined by its disguise: it presents itself as something useful so the user runs it willingly. A worm needs no such trick, since it propagates by itself, and a keylogger describes a payload rather than a method of getting in.

Answer: D

Correct answer: All of these

Norton, K7 and Quick Heal are all antivirus products.

Answer: A

Correct answer: Boot infectors

A boot sector virus writes itself into the boot record, so it is loaded before the operating system every time the machine starts and can destroy data from a position where nothing is yet in place to stop it. A stealth virus is defined by hiding from detection, which is a different property, and a trojan does not replicate at all.

Answer: D

Correct answer: All of the above

Each of the three threatens an electronic payment system in its own way: a virus can corrupt transaction data, a worm can consume the bandwidth the system depends on, and a trojan can capture card details or credentials while pretending to be legitimate software.

Answer: A

Correct answer: Report it as phishing/spam through your email provider

No legitimate service asks for a password by email, so such a message is phishing. Reporting it both protects the account and helps the provider block the sender for everyone else; merely deleting it does the first but not the second, and replying hands over exactly what the attacker asked for.

Answer: A

Correct answer: No

Antivirus software that shipped with the machine is out of date the moment the machine is sold, since new threats appear daily and its definitions were fixed at the factory. It has to be updated - along with the operating system's patches - before the machine can safely be exposed to the internet.

Answer: A

Correct answer: hard to assure identity of user on a remote system

Authentication is the problem of establishing that a user really is who the user claims to be, and it is genuinely hard across a network, where the system sees only the messages it is sent. Insertion and modification are kinds of attack on data rather than the process of establishing identity.

Answer: A

Correct answer: Receiver

Confidentiality means the content is intelligible only to the party it is addressed to. Anyone else who intercepts it should obtain nothing but ciphertext.