

While some simple ransomware may lock the system in a way that is not difficult for a knowledgeable person to reverse, more advanced malware uses a technique called cryptoviral extortion, which encrypts the victim's files, making them inaccessible, and demands a ransom payment to decrypt them.Ī computer virus is a type of malware that propagates by inserting a copy of itself into and becoming part of another program. Ransomware is a type of malicious software that threatens to publish the victim's data or perpetually block access to it unless a ransom is paid. These and other classes of malicious software are described below. The difference is that a worm operates more or less independently of other files, whereas a virus depends on a host program to spread itself.

To be classified as a virus or worm, malware must have the ability to propagate. These types of programs are able to self-replicate and can spread copies of themselves, which might even be modified copies. Two of the most common types of malware are viruses and worms. Malware should also not be confused with defective software, which is intended for legitimate purposes but contains errors or "bugs." Classes of Malicious Software In addition to damaging data and software residing on equipment, malware has evolved to target the physical hardware of those systems. Damage from malware varies from causing minor irritation (such as browser popup ads), to stealing confidential information or money, destroying data, and compromising and/or entirely disabling systems and networks. Some of the more commonly known types of malware are viruses, worms, Trojans, bots, ransomware, backdoors, spyware, and adware. The vast majority, however, are installed by some action from a user, such as clicking an email attachment or downloading a file from the Internet. Others are installed by exploiting a known vulnerability in an operating system (OS), network device, or other software, such as a hole in a browser that only requires users to visit a website to infect their computers. Malware can infect systems by being bundled with other programs or attached as macros to files.

There are many different classes of malware that have varying ways of infecting systems and propagating themselves.

Viruses, worms, Trojans, and bots are all part of a class of software called "malware." Malware is short for "malicious software," also known as malicious code or "malcode." It is code or software that is specifically designed to damage, disrupt, steal, or in general inflict some other "bad" or illegitimate action on data, hosts, or networks. Potentially Unwanted Programs or Applications
