Software designed to cause damage is known as malware. There are several types of malware, but boundaries between the different categories are tending to blur, as malware evolves to avoid detection. Thomas (2018) describes the following 4 types.
The best-known type is probably the virus. This is a piece of software that has been written to attack software on your computer, often with the specific intention of causing harm – deleting files, for example. A virus attaches itself to other software on your computer and activates when that software is run. Viruses are so called because they are designed to spread quickly and easily from one computer to another via internet connections or external storage devices such as memory sticks.
Another type of malware is the worm. This is a piece of malicious software that runs ‘in the background’, doing some damage to your computer even though you may not realise it is running. Worms can make copies of themselves, and those copies can spread via an internet connection. A worm typically consumes resources by running on a computer; in a major attack, all of a computer’s processing resources could be used in running the worm and its copies.
The trojan is a digital equivalent of the legendary wooden horse that smuggled the Greek soldiers into Troy. It appears to be legitimate software, such as a screensaver, but behind the scenes it is causing damage – perhaps allowing someone else to gain control of the computer, copying personal information, deleting information, or using email software to pass itself on to other computers.
Finally ransomware is a type of malware that prevents a user from accessing their computer either by locking the computer screen or by blocking access to computer files until a ‘ransom’ is paid. Typically, this form of malware is used to extort money from the user to ‘ransom’ the computer, but it could also be something relatively minor, such as being obliged to complete a survey.
Image by funstarts33 from Pixabay.
Thomas, E. (2018) ‘Part 1: Living in a digital world’, TM111, Block 1: The digital world, Milton Keynes, The Open University.