Even if we install something from a reliable source, if we do not pay attention to the request for permission to install other packaged software at the same time, we could install software that we do not need. This additional software is often presented as a necessary component, but it is not usually.
There are also other situations of infection with malware of which the user is not at fault, because it is even possible that the mere fact of visiting a malicious website and seeing a page or an advertising sign results in an involuntary download of malware.
These are the most common malefactors in the malware dishonesty gallery:
Adware is an unwanted software designed to show ads on your screen, usually in a browser. It usually uses a surreptitious method: it is pretended to be legitimate, or it is added to another program to deceive the user and install himself on his PC, tablet or mobile device.
Spyware is malware that observes the user's activities on the computer in secret and without permission, and communicates them to the author of the software.
A virus is malware that is attached to another program and, when executed - normally without the user's warning - it is replicated by modifying other programs on the computer and infecting them with its own bits of code.
Worms are a type of malware similar to viruses, which replicates on its own in order to spread through other computers on a network, usually causing damage and destroying data and files.
A Trojan is one of the most dangerous types of malware. It is usually presented as something useful to deceive the user. Once in the system, the attackers who hide behind the Trojan obtain unauthorized access to the infected computer and from there they are used to steal financial information or install threats such as viruses and ransomware.
Ransomware is a type of malware that blocks user access to the device or encrypts its files and then forces it to pay a ransom to return them. Ransomware has been recognized as the preferred weapon of cybercriminals because it demands a fast and profitable payment in cryptocurrency that is difficult to track.
Rootkit is a type of malware that provides the attacker with administrator privileges on the infected system. Normally, it is also designed to remain hidden from the user, other system software and the operating system itself.
A keystroke logger is malware that records all user keystrokes, stores the information collected and sends it to the attacker, who searches for confidential information, such as usernames, passwords or credit card details.
Malicious cryptocurrency mining, or cryptojacking, is an increasingly prevalent malware installed by a Trojan. It allows other people to use their computer to do cryptocurrency mining like bitcoin or monero. A malicious cryptocurrency mining program steals your resources to make money.
Exploits are a type of malware that exploits the errors and vulnerabilities of a system so that the creator of the exploit can take over. These are linked, among other threats, to malicious advertising. Subsequently the harmful content tries to install on the computer after an involuntary download. It is not even necessary to click. All you have to do is visit a good site the wrong day.
