Computer Security Questions and Answers

Answer: B

The purpose is to steal private and confidential data for blackmailing and extortion.

Malware such as viruses, spyware and ransomware is spread to gain unauthorised access to systems, copy or lock data, and then use it for fraud, blackmail or ransom demands.

The other options describe what security professionals do, not criminals. Improving system security and fixing vulnerabilities are the work of defenders, and helping organisations recover lost data is the job of backup and recovery services. A cyber criminal exploits vulnerabilities rather than fixing them.

Answer: A

Another term for antivirus software is Anti-Malware.

Malware is the umbrella term for malicious software: viruses, worms, Trojans, spyware, ransomware and so on. Modern antivirus programs detect and remove all of these, so the two names are used interchangeably.

'Malware detection program' describes only one function, detection, and not removal. A spyware eliminator deals with one kind of malware only. Network protection software, such as a firewall, controls network traffic rather than scanning for and removing malicious programs.

Answer: A

The answer is keyloggers.

A keylogger records every key pressed on a keyboard, capturing passwords and other private data. It can be software, a malicious program running in the background, or hardware, a small device plugged in between the keyboard and the computer.

A virus, a Trojan and adware are always software. A virus attaches itself to files and spreads, a Trojan disguises itself as a useful program, and adware pushes unwanted advertisements; none of them exists as a physical device.

Answer: A

The keyed answer is Only worms propagate via the network.

A worm is a standalone program that copies itself from computer to computer across a network on its own, using security holes, with no host file and no user action. A virus has no such ability: it attaches to a host file or program and spreads only when that file is run or shared, for instance as an email attachment.

The other options are false. Worms do not need a host application. Viruses cannot replicate without human action such as opening an infected file. And worms spread without anyone executing infected files. The keyed option is the only one left, read as self-propagation across a network.

Answer: C

The correct matching is a-3, b-1, c-5, d-2, e-4.

• Signature-based detection checks files against a database of known malware signatures, the Virus Definition File, which needs regular updates (3).
• Sandbox detection runs a suspicious file in an isolated virtual environment and watches its behaviour (1).
• Data mining techniques classify a file's behaviour as benign or malicious (5).
• Heuristics examine a suspected program's code and compare it with code from known viruses (2).
• Real-time protection monitors applications while they run (4).

Signature-3 and sandbox-1 occur together in only one option.

Answer: C

The hacker who exploits flaws for personal gain is a black hat hacker.

Black hat hackers break into systems without permission and use what they find for profit, theft or damage.

A white hat hacker, also called an ethical hacker, tests systems with the owner's permission and reports the weaknesses so they can be fixed. A grey hat hacker sits in between: they may probe a system without permission, but usually disclose what they find rather than exploit it for gain. That leaves black hat as the only option describing exploitation for personal benefit.

Answer: A

Correct answer: Phishing scams

Phishing is impersonation used to extract information: the attacker pretends to be a bank or a colleague and asks for the credentials directly. Spyware takes information without asking, which is a different method.

Answer: B

Correct answer: time bomb

A logic bomb lies dormant until some condition is met. When the condition is a date or a time, it is called a time bomb - the Friday the 13th and Michelangelo viruses are the classic examples. A trojan horse is defined by disguise rather than by timing.

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.