Named after the Trojan Horse of Greek legend, a trojan is a program or file that has, or appears to have, a useful or desirable function to encourage the user to install the program or open the file. In the background however, it also silently performs unauthorized actions (its payload), without the user's knowledge or consent.
Depending on the settings of your F-Secure security product, it will either automatically delete, quarantine or rename the suspect file, or ask you for a desired action.
More scanning & removal options
More information on the scanning and removal options available in your F-Secure product can be found in the Help Center.
You may also refer to the Knowledge Base on the F-Secure Community site for more information.
A trojan is usually deliberately designed by its author to appear authentic and attractive. For example, it may appear to be a screensaver, a service pack, an application update and so on. Some trojans may mimic or entirely copy the style and branding of popular legitimate programs or files, to fool the user into believing that it is authentic. Some trojans (particularly on the Android platform) are repackaged or trojanized versions of legitimate applications which have had malicious components inserted into them.
Once installed or opened, the trojan may perform its promised function, or display a decoy document to distract the user. In the background however, it also silently performs unauthorized actions (its payload), without the user's knowledge or consent.
Depending on its creator's intent, a trojan's payload can range from:
- Mildly annoying pranks, like changing desktop icon positions, to
- Serious, user-inhibiting actions, like disabling the keyboard or mouse, to
- Critically destructive actions, like erasing files or stealing data
A specialized type of trojan is ransomware, which attempts to steal, delete or encrypt the user's own files; the user must subsequently 'ransom' these files back from the attacker, usually by monetary payment. For more information about this type of malware, see:
- Threat Description: Ransomware
- Article: Crypto-ransomware
- Article: Removing 'police-themed' ransomware
Generic Trojan Detections
Generic Detections are a type of detection used by antivirus programs to identify files with malicious characteristics.
Unlike single-file detections which can only identify unique files, Generic Detections can look for broadly similar code or behavioral patterns in dozens or even hundreds of suspect programs or files, to efficiently determine their potential for causing harm.
A Generic Detection for trojans may use various naming formats. Some examples are: