A Trojan Horse is a malicious application that is designed to enable hackers to remotely access the target computer system. A Trojan Horse neither replicates nor copies itself, it must be sent by someone or carried by another program and may arrive in the form of a software of some sort. Trojans may arrive via unwanted downloads on compromised websites or install via online games or other internet-driven applications.
The malicious functionality of a Trojan Horse may be anything undesirable for a computer user, including data destruction or compromising a system by providing a means for another computer to gain access, thus bypassing normal access controls.
A Trojan Horse program has the appearance of having a useful and desired function. While it may advertise its activity after launching, this information is not apparent to the user beforehand. Secretly the program performs other, undesired functions.
Common things that a Trojan Horse may do include:
- Modification of files
- Data theft (personal information, credit card information, used passwords...)
- Keyboard input logging
- Installation of other software (including malware)
Generally, most Trojan Horses can be detected and removed by AVG.