“Malware” is short for malicious software and used as a single term to refer to virus, spyware, worm etc. Malware is designed to cause damage to a stand alone computer or a networked computer. So wherever a malware term is used it means a program which is designed to damage your computer it may be a virus, worm or Trojan.
Virus:- Virus is a program written to enter to your computer and damage/alter your files/data. A virus might corrupt or delete data on your computer. Viruses can also replicate themselves. A computer Virus is more dangerous than a computer worm as it makes changes or deletes your files while worms only replicates itself with out making changes to your files/data.
Viruses can enter to your computer as an attachment of images, greeting, or audio / video files. Viruses also enters through downloads on the Internet. They can be hidden in a free/trial softwares or other files that you download.
So before you download anything from internet be sure about it first. Almost all viruses are attached to an executable file, which means the virus may exist on your computer but it actually cannot infect your computer unless you run or open the malicious program. It is important to note that a virus cannot be spread without a human action, such as running an infected program to keep it going.
Worms:- Worms are malicious programs that make copies of themselves again and again on the local drive, network shares, etc. The only purpose of the worm is to reproduce itself again and again. It doesn’t harm any data/file on the computer. Unlike a virus, it does not need to attach itself to an existing program. Worms spread by exploiting vulnerabilities in operating systems.
Due to its replication nature it takes a lot of space in the hard drive and consumes more cpu uses which in turn makes the pc too slow also consumes more network bandwidth.
Trojans: – A Trojan horse is not a virus. It is a destructive program that looks as a genuine application. Unlike viruses, Trojan horses do not replicate themselves but they can be just as destructive. Trojans also open a backdoor entry to your computer which gives malicious users/programs access to your system, allowing confidential and personal information to be theft.
Trojan horses are broken down in classification based on how they infect the systems and the damage caused by them. The seven main types of Trojan horses are: • Remote Access Trojans • Data Sending Trojans • Destructive Trojans • Proxy Trojans • FTP Trojans • security software disabler Trojans • denial-of-service attack Trojans
Adware: – Generically adware is a software application in which advertising banners are displayed while any program is running. Adware can automatically get downloaded to your system while browsing any website and can be viewed through pop-up windows or through a bar that appears on a computer screen automatically. Adwares are used by companies for marketing purpose.
Spyware: – Spyware is a type of program that is installed with or without your permission on your personal computers to collect information about users, their computer or browsing habits tracks each and everything that you do without your knowledge and send it to remote user. It also can download other malicious programs from internet and install it on the computer. Spyware works like adware but is usually a separate program that is installed unknowingly when you install another freeware type program or application.