Computer Security Questions and Answers

Answer: D

Such software is known as a virus.

A computer virus is malicious code written deliberately to disrupt or damage computers. It attaches itself to a program or file and, when that is run or shared, copies itself to other files and computers, spreading from machine to machine and corrupting data or slowing systems.

A search engine finds information on the web, chat software lets users exchange messages, and e-mail is a way of sending messages. None of them is disruptive software, although e-mail attachments are a common way for viruses to spread.

Answer: B

The key gives B, offender computer skills and victim ignorance of computer technology.

I could not find a published source that names these as the two essential features of cyber crime, so I cannot confirm the key from a reference. Another option, A (computer technology as the modus operandi and the intangibility of the environment), also describes cyber crime in a way that is common in textbooks. The explanation therefore follows the Commission's key and does not claim more than that.

Options C and D are the weakest: hardware and software are the equipment a computer uses, not features of a crime, and hackers and crackers are kinds of offender, not features. Option B at least names two conditions that make a cyber offence possible, the offender's skill and the victim's lack of knowledge.

Answer: C

The term is cracker.

A cracker is a person who breaks into computer systems without authorisation with malicious or criminal intent, for example to steal data, deface websites or commit fraud. The term was coined to distinguish such people from hackers in the original sense of skilled programmers who explore systems out of curiosity.

A white hat is an ethical hacker who tests systems with permission to find and fix weaknesses. 'Hacker' is the general term and does not by itself imply criminal intent in the sense the question draws. Stacker was a disk compression program, not a kind of intruder.

Answer: D

It is known as a denial of service attack.

In a denial of service (DoS) attack, an attacker floods a website or server with so much fake traffic or so many requests that it is overwhelmed and cannot serve genuine users. When the traffic comes from many compromised computers at once (a botnet), it is a distributed denial of service (DDoS) attack.

A virus is self-replicating malicious code, a Trojan horse is malicious software disguised as a useful program, and cracking means breaking into systems or breaking software protection. None of them describes making a site unavailable by flooding it.

Answer: A

Blowfish is a Symmetric Encryption Algorithm.

Blowfish, designed by Bruce Schneier in 1993, is a symmetric-key block cipher: the same secret key, of 32 to 448 bits, is used both to encrypt and to decrypt 64-bit blocks of data. It was designed as a fast, free alternative to DES.

Hashing algorithms (such as SHA) produce fixed-length digests and cannot be decrypted, digital signature algorithms (such as DSA) authenticate messages, and asymmetric algorithms (such as RSA) use a public and private key pair. Blowfish is none of these.

Answer: D

Virtual keyboards protect against all three, so the answer is All of the above.

A virtual (on-screen) keyboard lets the user enter text, such as a password, by clicking keys with the mouse rather than pressing physical keys. Keyloggers, which are often delivered by Trojan programs or are a form of spyware, record keystrokes, so they cannot capture input that is never typed.

This is why banking sites offer virtual keyboards for passwords: they guard against password theft, Trojans and spyware that log keys. Choosing any one alone would be incomplete.

Answer: B

Such an e-mail is an example of Spoofing.

E-mail spoofing forges the sender's address in the message header, so that the mail appears to come from one source when it was actually sent by someone else.

Phishing is the wider fraud of tricking people into revealing passwords or bank details, which often uses spoofed mail but is not the same thing. Spamming is sending bulk unsolicited messages, and sniffing is intercepting data travelling over a network.

Answer: A

Tricking users into revealing sensitive information is a Phishing attack.

In phishing, the attacker sends an email, message or link that pretends to come from a trusted source, such as a bank, and lures the victim into entering passwords, card numbers or one-time passwords on a fake page. It relies on deceiving people rather than breaking software.

An SQL injection attack inserts malicious database commands into input fields to read or alter data, and a denial-of-service (DoS) attack floods a system with traffic to make it unavailable. Neither depends on tricking a user, so 'None of the above' is also wrong.

Answer: B

A firewall exists to block unauthorized access to a network.

A firewall, in hardware or software, sits between a trusted network and untrusted ones such as the internet. It examines incoming and outgoing traffic against a set of rules, allowing permitted connections and blocking the rest, so that intruders and unwanted traffic are kept out.

Allowing unrestricted access is the opposite of a firewall's purpose. Making backups of data is the job of backup systems, not firewalls, so 'None of the above' is wrong as well.

Answer: D

They are names of ransomware attacks.

Ransomware is malicious software that encrypts a victim's files and demands payment for the key. WannaCry spread worldwide in May 2017 through a Windows vulnerability, Bad Rabbit struck mainly in Russia and Ukraine later in 2017, and LockBit is a ransomware group and software behind many attacks since 2019.

The names have nothing to do with the Israel-Palestine conflict, epidemics or nuclear war; they appear in cyber-security news.