Types of Virus & Malware
Backdoor: these are remote administration programs that allow you to control the infected computer from the network. These programs are not able to replicate themselves, but have the characteristic of keeping ports open on the computers where they have been run. These ports, entry points, can be used by users connected to the network to access data and programs on the computer where the Backdoor has been performed. Backdoors can have various functions such as: sending and receiving files, deleting archives, executing payloads or carrying viruses within the system.
Dialer: these are programs that modify the Internet connection by changing the telephone number of the connection. They are especially dangerous for those who connect to the Internet using analog and / or ISDN modems. For those who connect on the ADSL line they can cause the disconnection of the connection.
Fraudtool: consist of so-called 'rogue-antivirus' programs, which pretend to be AntiVirus solutions. After they are installed on the computer, they pretend to «find» one or more viruses, even on absolutely clean systems, and propose to buy their paid version to immunize / disinfect their computer. In addition to direct user fraud, these programs also have adware functionality within them.
Trojan: These are programs that intentionally hide their malicious actions from the user, making them believe they are performing other functions. Trojans are generally unable to spread autonomously as they do not possess the ability to infect. Generally the purpose of a Trojan is to execute its payload.
Ransomware: This is a type of malware that restricts access to the computer system it infects, demanding a ransom to be paid to the creator of the malware, so that the restriction can be removed. Some variants of this infection encrypt files on the system's hard drive (Cryptomalware), while some may simply lock the system and display messages intended to convince the user to pay.