Computer Virus:
computer virus is a computer program that can copy itself and infect a computer. The term "virus" is also commonly but erroneously used to refer to other types of malware, including but not limited to adware and spyware programs that do not have the reproductive ability. A true virus can spread from one computer to another (in some form of executable code) when its host is taken to the target computer; for instance because a user sent it over a network or the Internet, or carried it on a removable medium such as a floppy disk, CD,DVD, or USB drive.
Viruses can increase their chances of spreading to other computers by infecting files on a network file system or a file system that is accessed by another computer.
Malware includes computer viruses, computer worms, Trojan horses, most rootkits, spyware, dishonest adware and other malicious and unwanted software, including true viruses. Viruses are sometimes confused with worms and Trojan horses, which are technically different. A worm can exploit security vulnerabilities to spread itself automatically to other computers through networks, while a Trojan horse is a program that appears harmless but hides malicious functions. Worms and Trojan horses, like viruses, may harm a computer system's data or performance. Some viruses and other malware have symptoms noticeable to the computer user, but many are surreptitious or simply do nothing to call attention to themselves. Some viruses do nothing beyond reproducing themselves.
Mobile Virus:
Mobile virus is an electronic virus that targets mobile phones or wireless-enabled PDAs.
As wireless phone and PDA networks become more numerous and more complex, it has become more difficult to secure them against electronic attacks in the form of viruses or other malicious software (also known as malware).
• Cabir: Infects mobile phones running on Symbian OS. When a phone is infected, the message 'Caribe' is displayed on the phone's display and is displayed every time the phone is turned on. The worm then attempts to spread to other phones in the area using wireless Bluetooth signals.
• Duts: A parasitic file infector virus and is the first known virus for the PocketPC platform. It attempts to infect all EXE files in the current directory (infects files that are bigger than 4096 bytes).
• Skulls: A trojan horse piece of code. Once downloaded, the virus, called Skulls, replaces all phone desktop icons with images of a skull. It also will render all phone applications, including SMSes and MMSes useless.
• Commwarrior: First worm to use MMS messages in order to spread to other devices. Can spread through Bluetooth as well. It infects devices running under OS Symbian Series 60. The executable worm file, once launched, hunts for accessible Bluetooth devices and sends the infected files under a random name to various devices.
