Malware: Malicious software. Malware (malicious software), is software used or created to disrupt computer operation, gather sensitive information, or gain access to private computer systems. It can appear in the form of code, scripts, active content, and other software. 'Malware' is a general term used to refer to a variety of forms of hostile, intrusive, or annoying software. Malware includes computer viruses, worms, trojan horses, spyware, adware, and other malicious programs. In law, malware is sometimes known as a computer contaminant, as in the legal codes of several U.S. states. Malware is not the same as defective software, which is software that has a legitimate purpose but contains harmful bugs that were not noticed before release. However, some malware is disguised as genuine software, and may come from an official company website. An example of this is software used for harmless purposes that is packed with additional tracking software that gathers marketing statistics. Malware has caused the rise in use of protective software types such as anti virus, anti-malware, and firewalls. Each of these are commonly used by personal users and corporate networks in order to stop the unauthorized access by other computer users, as well as the automated spread of malicious scripts and software. Your computer may comprise multiple kinds of threats affecting your data, so you must understand what types of malware exist and how these work. Classic viruses: Programs that infect other programs by adding code to take control after the execution of infected files. The main purpose of a virus is infecting. The speed of propagation of the virus is somewhat lower than that of the worms. bomb: Refers to a programming statement like " time bomb".   Malware of this type. Work under one condition. It is defined by the authors.  Example The Format Hard disk on the Run Program .... after 5 times and so on. Or the date it set.Program....ครบ5ครั้งเป็นต้น หรือกำหนดตามวันที่ก็มี Jokes / Pranks: This group includes programs that do not cause direct damage to the computers they infect. However, show false warnings about alleged harm occurred or occur. May be messages warning users that the disks are formatted, which has found a virus or symptoms of infection have been detected. The possibilities are limited only by the sense of humor the author of the virus. Rootkits: A rootkit is a collection of programs used by a hacker to evade detection while seeking to gain unauthorized access to a computer. This is accomplished in two ways: replacing system files or libraries, or by installing a kernel module. The hacker installs the rootkit after, getting a similar access to the user, usually crack a password or exploiting a vulnerability, which allows you to use other credentials to gain access to root or administrator. Network worms: This type of malware uses to distribute network resources. His name means they can penetrate from one computer to another like a worm. They do so via email, instant messaging systems, file-sharing networks (P2P), IRC channels, local networks, global networks, etc. Its propagation speed is very high. To penetrate a computer, the worm tries to obtain the addresses of other computers on the network to start sending copies. They also tend to use the data book contacts email client. Most worms spread as files but there is a small amount of worms that spread in the form of network packets and directly penetrate the victim computer's RAM, which then execute your code. Riskware: They are not malicious but contain a potential threat. In certain situations put your data at risk. Include remote administration programs, bookmarks, etc.     Trojans: This class of malware includes a variety of programs that perform actions without the user's knowledge and without their consent, collect data and send them to the criminals, destroy or alter data with criminal intent, causing damage to computer operation or use computer resources for criminal purposes, such as mass mailing of unsolicited email. They are classics because virus does not infect other programs or data. Trojans can not penetrate to the equipment itself, but spread by criminals under the wing of a software "desirable" and are capable of causing much more harm than classic viruses. Spyware: Software that allows the collection of information about a user or organization in an unauthorized manner. Their presence can be completely invisible to the user and they can collect data on user actions, the contents of the hard drive, installed software, quality and connection speed, etc. Adware: Display advertising to the user. Most Adware programs are installed as free software. The advertisement appears in the interface. Sometimes they can collect and send user's personal data. Phishing: Is a variety of spyware that spreads via email to receive confidential user data, of a preferred bank. The phishing emails are designed to look like legal correspondence sent by banking organizations, or some well-known brands. These emails contain a link that redirects users to a fake page that will ask to some sensitive data such as the number of credit card.   Other malicious programs: There are a number of programs that do not directly affect computers, but are used to create viruses, Trojans or illegal activities such as operating system attacks and penetrate other computers, etc. Spam: Unsolicited messages from unknown senders are sent en masse for advertising, political propaganda, seeking help, and more. Another kind of spam makes proposals relating to various illegal operations. Emails are also dedicated to steal passwords or credit card numbers, chain letters, etc. Spam creates an additional burden on email servers and can cause loss of desired information. Artile by : Herry Willson (Understanding Malware: The Malicious Software>www.allthewebsites.) Recommended : Wikipedia.org Malware , computer viruses, worms, trojan horses, spyware, adware,