Malware is a term used to describe malicious software that is designed to disrupt the normal computer operation, gather user’s personal information, gain unauthorized access to system resources and exhibit other annoying activities. It can appear in the form of code, scripts, active content, and other software. They are designed in such a way that a malware can perform all these activities without the owner’s permission.
Malware is also referred to as scumware. It has been intentionally designed to change a user's settings without their permission. A computer, mobile phone or any device can be infected by malware by visiting an infected website, downloading infected software, or installing infected software. Sometimes, even by using the USB drives that are portable and connected to virus infected device could spread infection to the system.
Forms of Malware
Some of the most prevalent forms of malware include computer viruses, worms, Trojans and spyware.
Viruses and worms
Viruses and worms are referred as the contagious threat and defined by their behavior. They are a type of malicious software designed to spread on the device without the user’s knowledge. A virus infects legitimate software and when this software is used on the computer or any device it spreads the virus. Viruses need used user action like executing, downloading, copying etc. to spread.
Computer worms, on the other hand, spread without user action. Both viruses and worms can carry a “payload”, which is a malicious code designed to do damage.
Trojans and Rootkits
Trojans and rootkits are grouped together and often defined as the masked threat since as they both hide to attack on computers. Trojan Horses are software pretend to be nonthreatening applications and hence users download them thinking they will get a useful piece of software and end up with a malware infected computer.
Rootkits are different, they are a masking technique for malware, but do not contain damaging software. These are designed to hide the malware, so that it could go unnoticed by antivirus detection and removal programs.
Spyware and keyloggers
Spyware and keyloggers are a form of malware used in malicious attacks like identity theft, social engineering and phishing etc. These threats are designed to steal money from unknowing computer users, businesses and banks. Hence, they are often referred as financial threat.
What does malware do?
The exact purpose of any piece of malware is dependent on what type of malware it is. The effects of malwares differ according to the specific type of malware that has infected the computer. It can delete a competing software program and even cause a software program to stop working, or leave a computer open to attacks.
A Spyware would gather data and report it back to somewhere. Adware displays unsolicited ads and other undesired marketing ads. Viruses have a whole host of sub-classes that are determined by how they infect a computer and their effect can be known only after they have done so.