Malware, also called malicious software, is a general term for software that is created for the purpose of causing damage on its users. The victims have no idea they are running it on their computer systems.

Malware includes computer Trojans, worms, viruses, scareware, ransomware, spyware, adware, cryptocurrency miners, and other programs intended to exploit computer resources for nefarious purposes.

Viruses

Computer viruses are programs that replicate their own code into computer systems when executed. They infect the computers  through  software. For instance, a virus can be included in the executable file of a microsoft word document. So that when the word document is executed or run, the virus is executed alongside without one knowing.viruses can also infect the boot sector of an harddrive.

Because virus can spread on their own, if not checked will eventually render the computer system unusable

Viruses need a host or software to spread, that is to say , once the infected software or program is not run. The virus cannot run as well.

Worms

Computer worms are pieces of malicious  programs  that can propagate themselves without a host.they often attack computer networks and internet connections looking for vulnerabilities.

Worms can consume large amounts of network bandwidth slowing down internet connections in the process.  Worms can steal information without modifying program data.

Trojans

Trojans (named after the  historical Trojan horse) is a malicious software that disguises itself as genuine. It can also be hidden within a non malicious software. Trojans can be spread by tricking people into installing an app, clicking on a link or some email attachment sent into your inbox.

Unlike viruses and worms which can self propagate, trojans propagate through the mistakes of humans.

Ransomware

Ransomware as the name implies, is  a malware that steals sensitive information, or encrypts files then tells the victim to pay some ransom to some criminal before stolen information can be returned or decrypted. 

Scareware

Scareware  is a malicious program that scares people into taking some action. For example a message can suddenly appear on your phone stating it has a virus and  tricks you into clicking a link to download antivirus. But that link actually leads to the malicious program. 

Spyware

Spyware is  a software that, without permission, collects information from your device. Information collected can include, keylogger, screen images, videos, audio from a microphone, and so on.

Cryptocurrency miners

Cryptocurrency miners are malware that steals cryptocurrency by infecting the CPU of its victims. 

Adware

Adware is software that generates revenue for the party operating. It displays adverts on your device usually after download of a free software. The adware is installed and run without permission.  

Blended malware

Blended malware refers to a technology that uses different types of malicious programs to run. For instance, a software comprising viruses, worms and trojans.

Zero day malware

Zero day malware is any malicious program that exploits a loophole not previously known to the public or to the creators/sellers of the technology containing the defect.