Trojans are non-replication programs; they don’t reproduce their own codes by attaching themselves to other executable codes. They operate without the permissions or knowledge of the computer users.
Trojans hide themselves in healthy processes. However we should underline that Trojans infect outside machines only with the assistance of a computer user, like clicking a file that comes attached with email from an unknown person, plugging USB without scanning, opening unsafe URLs.
Trojans have several malicious functions −
They create backdoors to a system. Hackers can use these backdoors to access a victim system and its files. A hacker can use Trojans to edit and delete the files present on a victim system, or to observe the activities of the victim.
Trojans can steal all your financial data like bank accounts, transaction details, PayPal related information, etc. These are called Trojan-Banker.
Trojans can use the victim computer to attack other systems using Denial of Services.
Trojans can encrypt all your files and the hacker may thereafter demand money to decrypt them. These are Ransomware Trojans.
They can use your phones to send SMS to third parties. These are called SMS Trojans.
If you have found a virus and want to investigate further regarding its function, then we will recommend that you have a look at the following virus databases, which are offered generally by antivirus vendors.
Kaspersky Virus database − https://www.kaspersky.com
F-secure − https://www.f-secure.com
Symantec – Virus Encyclopedia − https://www.symantec.com
Install a good antivirus and keep it updated.
Don’t open email attachments coming from unknown sources.
Don’t accept invitation from unknown people in social media.
Don’t open URLs sent by unknown people or URLs that are in weird form.