What is Malware?

Malware is malicious software that has been created with the intent to compromise computer systems by stealing data, taking control or causing harm to the computer system or network. There are various types of malware each with a specific role in causing harm to a device or organisations computer network.


This type of malware specifically targets the victim’s data by blocking access to it and demanding a ransom is paid to unblock access. The data itself is encrypted and can only be accessed by paying the ransom to get the decryption key. An alternative to retrieving the data would be to restore from a recent backup. A computer can get infected by ransomware by downloading a file or through a vulnerability in a network service or operating system. A recent example of this was the Wannacry outbreak in May 2017 which affected the NHS.



Adware is short for advertising-supported software, this type of malware automatically delivers online advertisements to the user’s device. The most common form of this are pop-ups within a web browser and software offers by installing free versions of software programs. The purpose of this type of malware is to generate revenue however adware can come bundled with spyware which is capable of stealing information.



Spyware is a type of malware that is used to gather/steal information about an individual or organisation. Spyware installs itself on a system by either exploiting software vulnerabilities or deceiving the user.



A virus is similar to a worm in that it is able to use the computer network to spread to other devices, a virus is able to deal more damage as it attaches itself to exploited programs and executes code. Virus’ are used to steal information, bring computers and networks to a halt, steal money, force pop-ups and more.



A worm is a malicious computer program that replicates itself over the computer network, they are also classified as a type of computer virus. The program tends to use security flaws and failures to copy itself to other computers on the network. Worms tend to consume network bandwidth and overload web servers bringing everything to a halt.



Rookits are designed to remotely control or access a computer without the user’s content or knowledge. Once a rookit is installed on a computer they are able to steal information, install malicious software and modify system settings. To prevent rootkits from getting installed it is important to make sure the computers operating system is kept up to date, the device is regularly patched against any vulnerabilities and virus definitions are up to date.

TOPICS: Cybercrime, Ransomware, Cyber security, Malware

Written By: Doherty

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