You have noticed that your computer is acting erratically and normal tasks (e.g., open a document/application), are taking a little bit longer to perform.


2::It is a computer virus that frequently attack computers.
3::It is a malicious software that allows other programs to control your computer by misleading users of its true intent.
1::It is a malfunction of the software that makes it difficult to navigate the Internet.

A Trojan Horse is not a computer virus - although both computer viruses and Trojan Horses are malicious software (malware).

A Trojan Horse is an autonomous program that appears to be doing what the user wants, but is actually doing something else. Hence, this unwanted, hidden, additional function could allow other programs to control your computer by misleading users of its true intent. A characteristic example of a Trojan Horse is the case with the AIDS Trojan that encrypted the user’s data after a number of reboots, see: http://en.wikipedia.org/wiki/AIDS_(Trojan_horse) .

A Virus is a non-autonomous segment of code that will copy itself into a ‘host program’ when it is activated. Viruses often perform some type of harmful activity on infected hosts. The main difference is that viruses replicate and can thus infect other programs or devices of the users and others, while Trojans do not automatically replicate. A characteristic example is the so-called Melissa virus, see: https://en.wikipedia.org/wiki/Melissa_(computer_virus)

See also: https://www.enisa.europa.eu/topics/national-csirt-network/glossary/malware

 

This is the correct answer. A Trojan horse is an autonomous program that appears to be doing what the user wants, but is actually doing something else. Hence, this unwanted, hidden, additional function could allow other programs to control your computer by misleading users of its true intent. A characteristic example of a Trojan Horse is the case with the AIDS Trojan that encrypted the user’s data after a number of reboots, see: http://en.wikipedia.org/wiki/AIDS_(Trojan_horse). 

See also: https://www.enisa.europa.eu/topics/national-csirt-network/glossary/malware

 

Trojan horses are not malfunctions of the computer software. A Trojan horse is an autonomous program that appears to be doing what the user wants, but is actually doing something else. Hence, this unwanted, hidden, additional function could allow other programs to control your computer by misleading users of its true intent. A characteristic example of a Trojan Horse is the case with the AIDS Trojan that encrypted the user’s data after a number of reboots, see: http://en.wikipedia.org/wiki/AIDS_(Trojan_horse).

See also: https://www.enisa.europa.eu/topics/national-csirt-network/glossary/malware

 


So you called a friend of yours who is a computer technician and always helps you when your computer has problems. After a careful inspection he told you that your computer has been infected by a ‘Trojan Horse’.

You wonder what a ‘Trojan Horse’ could be?