About MalWareAll computer viruses are Malware, but not all Malware are viruses. Malware encompases a much broader spectrum of MALicious softWARE, of which viruses are just a part of.
"Virus" is a general catch all term that not only refers to true viruses, but also malware, spyware, etc., however there are some definite differences between them.
Malware includes computer viruses, as we have explained in the >VIRUS< section, but also:
* Adware displays unwanted advertisements or pop ups after the program is downloaded, with or without the users consent or knowledge. Adware that observes the computer user's activities without their consent and reports it to the software's author is called spyware.
* Spyware lurks in the background of a computer, collects information, displays ads, or hijacks browsers. These programs are designed to monitor users' web browsing, display unsolicited advertisements, or redirect affiliate marketing revenues to the spyware creator. Spyware programs do not spread like viruses; instead they are generally installed by exploiting security holes. They can also be packaged together with user-installed software, such as peer-to-peer applications.
* Ransomware / Scareware is a type of malware which infects your computer, displaying a fake, but genuine looking screen spoofing the FBI or other law enforcement agency, claiming your computer has been used for child pornography or other illegal activity, and locks your computer, rendering it unusable, and demands a ransom be paid to the creator of the malware in order for the lock to be removed. Some forms of ransomware encrypt files on the system's hard drive (cryptoviral extortion), while some may simply lock the system and display messages intended to coax the user into paying.
* Worms A computer worm is malware that is designed to replicate itself and spread to other computers, usually using a network, preying on security vulnerabilities on target computers to infect them. Unlike a computer virus, it does not need to attach itself to an existing program, however a worm can carry a "payload", such as a virus or it will install a backdoor in the infected computer to allow the creation of a "zombie" computer under control of the worm's creator. Networks of zombie machines are often referred to as BOTNETS, and are very commonly used to attack other networks, for example using DDoS (Distributed Denial of Service) attacks to bring down websites and other networks, or for sending junk email or other nefarious purposes. Worms are almost always harmful, even just by consuming bandwidth.
* Keyloggers Covert keystroke logging, software that monitors every keystroke you make on your computer, while you are totally unaware your actions are being monitored. Keyloggers exist in several categories: Hypervisor-based, Kernel-based, API-based, Form grabbing based, Memory injection based, Packet analyzers, Remote access software keyloggers.
* Trojan Horses or Trojans, are non-self-replicating malware program(s). They contain malicious code, usually resulting in loss or theft of data, usually with harm being caused to the system,as they usually act as a back door to the system. Malware is considered to be a trojan if the trojan does not attempt to inject itself into other files (computer virus) or otherwise propagate themselves (worm). The entire purpose of a Trojan is deceit.
As an example, you download a new program that says it converts emails to PDF files, but when you download and install it, it actually does something completely different in the background.