Virus, Spyware & Malware
Spyware
is computer software that is installed surreptitiously on a personal
computer to intercept or take partial control over the user's
interaction with the computer, without the user's informed consent.
While the term spyware suggests software that secretly monitors the user's behavior, the functions of spyware extend well beyond simple monitoring. Spyware programs can collect various types of personal information, such as Internet surfing habit, sites that have been visited, but can also interfere with user control of the computer in other ways, such as installing additional software, redirecting Web browser activity, accessing websites blindly that will cause more harmful viruses, or diverting advertising revenue to a third party. Spyware can even change computer settings, resulting in slow connection speeds, different home pages, and loss of Internet or other programs. In an attempt to increase the understanding of spyware, a more formal classification of its included software types is captured under the term privacy-invasive software.
In response to the emergence of spyware, a small industry has sprung up dealing in anti-spyware software. Running anti-spyware software has become a widely recognized element of computer security best practices for Microsoft Windows desktop computers. A number of jurisdictions have passed anti-spyware laws, which usually target any software that is surreptitiously installed to control a user's 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.
As stated above, the term "computer virus" is sometimes used as a catch-all phrase to include all types of malware, even those that do not have the reproductive ability. 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.
Malware, a portmanteau from the words malicious and software, is software designed to infiltrate or damage a computer system without the owner's informed consent. The expression is a general term used by computer professionals to mean a variety of forms of hostile, intrusive, or annoying software or program code.
Many computer users are unfamiliar with the term, and often use "computer virus" for all types of malware, including true viruses.
Software is considered malware based on the perceived intent of the creator rather than any particular features. Malware includes computer viruses, worms, trojan horses, most rootkits, spyware, dishonest adware, crimeware and other malicious and unwanted software. In law, malware is sometimes known as a computer contaminant, for instance in the legal codes of several American states, including California and West Virginia
Malware is not the same as defective software, that is, software which has a legitimate purpose but contains harmful bugs.
Preliminary results from Symantec published in 2008 suggested that "the release rate of malicious code and other unwanted programs may be exceeding that of legitimate software applications."According to F-Secure, "As much malware [was] produced in 2007 as in the previous 20 years altogether."Malware's most common pathway from criminals to users is through the Internet, by email and the World Wide Web.
The best-known types of malware, viruses and worms, are known for the manner in which they spread, rather than any other particular behavior. The term computer virus is used for a program which has infected some executable software and which causes that software, when run, to spread the virus to other executable software. Viruses may also contain a payload which performs other actions, often malicious. A worm, on the other hand, is a program which actively transmits itself over a network to infect other computers. It too may carry a payload.
These definitions lead to the observation that a virus requires user intervention to spread, whereas a worm spreads automatically. Using this distinction, infections transmitted by email or Microsoft Word documents, which rely on the recipient opening a file or email to infect the system, would be classified as viruses rather than worms.
Some writers in the trade and popular press appear to misunderstand this distinction, and use the terms interchangeably.
Capsule history of viruses and worms
Before Internet access became widespread, viruses spread on personal computers by infecting programs or the executable boot sectors of floppy disks. By inserting a copy of itself into the machine code instructions in these executables, a virus causes itself to be run whenever the program is run or the disk is booted. Early computer viruses were written for the Apple II and Macintosh, but they became more widespread with the dominance of the IBM PC and MS-DOS system. Executable-infecting viruses are dependent on users exchanging software or boot floppies, so they spread heavily in computer hobbyist circles.
The first worms, network-borne infectious programs, originated not on personal computers, but on multitasking Unix systems. The first well-known worm was the Internet Worm of 1988, which infected SunOS and VAX BSD systems. Unlike a virus, this worm did not insert itself into other programs. Instead, it exploited security holes in network server programs and started itself running as a separate process. This same behavior is used by today's worms as well.
With the rise of the Microsoft Windows platform in the 1990s, and the flexible macro systems of its applications, it became possible to write infectious code in the macro language of Microsoft Word and similar programs. These macro viruses infect documents and templates rather than applications, but rely on the fact that macros in a Word document are a form of executable code.
Today, worms are most commonly written for the Windows OS, although a small number are also written for Linus and Unix systems. Worms today work in the same basic way as 1988's Internet Worm: they scan the network for computers with vulnerable network services, break in to those computers, and copy themselves over. Worm outbreaks have become a cyclical plague for both home users and businesses, eclipsed recently in terms of damage by spyware.
While the term spyware suggests software that secretly monitors the user's behavior, the functions of spyware extend well beyond simple monitoring. Spyware programs can collect various types of personal information, such as Internet surfing habit, sites that have been visited, but can also interfere with user control of the computer in other ways, such as installing additional software, redirecting Web browser activity, accessing websites blindly that will cause more harmful viruses, or diverting advertising revenue to a third party. Spyware can even change computer settings, resulting in slow connection speeds, different home pages, and loss of Internet or other programs. In an attempt to increase the understanding of spyware, a more formal classification of its included software types is captured under the term privacy-invasive software.
In response to the emergence of spyware, a small industry has sprung up dealing in anti-spyware software. Running anti-spyware software has become a widely recognized element of computer security best practices for Microsoft Windows desktop computers. A number of jurisdictions have passed anti-spyware laws, which usually target any software that is surreptitiously installed to control a user's 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.
As stated above, the term "computer virus" is sometimes used as a catch-all phrase to include all types of malware, even those that do not have the reproductive ability. 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.
Malware, a portmanteau from the words malicious and software, is software designed to infiltrate or damage a computer system without the owner's informed consent. The expression is a general term used by computer professionals to mean a variety of forms of hostile, intrusive, or annoying software or program code.
Many computer users are unfamiliar with the term, and often use "computer virus" for all types of malware, including true viruses.
Software is considered malware based on the perceived intent of the creator rather than any particular features. Malware includes computer viruses, worms, trojan horses, most rootkits, spyware, dishonest adware, crimeware and other malicious and unwanted software. In law, malware is sometimes known as a computer contaminant, for instance in the legal codes of several American states, including California and West Virginia
Malware is not the same as defective software, that is, software which has a legitimate purpose but contains harmful bugs.
Preliminary results from Symantec published in 2008 suggested that "the release rate of malicious code and other unwanted programs may be exceeding that of legitimate software applications."According to F-Secure, "As much malware [was] produced in 2007 as in the previous 20 years altogether."Malware's most common pathway from criminals to users is through the Internet, by email and the World Wide Web.
The best-known types of malware, viruses and worms, are known for the manner in which they spread, rather than any other particular behavior. The term computer virus is used for a program which has infected some executable software and which causes that software, when run, to spread the virus to other executable software. Viruses may also contain a payload which performs other actions, often malicious. A worm, on the other hand, is a program which actively transmits itself over a network to infect other computers. It too may carry a payload.
These definitions lead to the observation that a virus requires user intervention to spread, whereas a worm spreads automatically. Using this distinction, infections transmitted by email or Microsoft Word documents, which rely on the recipient opening a file or email to infect the system, would be classified as viruses rather than worms.
Some writers in the trade and popular press appear to misunderstand this distinction, and use the terms interchangeably.
Capsule history of viruses and worms
Before Internet access became widespread, viruses spread on personal computers by infecting programs or the executable boot sectors of floppy disks. By inserting a copy of itself into the machine code instructions in these executables, a virus causes itself to be run whenever the program is run or the disk is booted. Early computer viruses were written for the Apple II and Macintosh, but they became more widespread with the dominance of the IBM PC and MS-DOS system. Executable-infecting viruses are dependent on users exchanging software or boot floppies, so they spread heavily in computer hobbyist circles.
The first worms, network-borne infectious programs, originated not on personal computers, but on multitasking Unix systems. The first well-known worm was the Internet Worm of 1988, which infected SunOS and VAX BSD systems. Unlike a virus, this worm did not insert itself into other programs. Instead, it exploited security holes in network server programs and started itself running as a separate process. This same behavior is used by today's worms as well.
With the rise of the Microsoft Windows platform in the 1990s, and the flexible macro systems of its applications, it became possible to write infectious code in the macro language of Microsoft Word and similar programs. These macro viruses infect documents and templates rather than applications, but rely on the fact that macros in a Word document are a form of executable code.
Today, worms are most commonly written for the Windows OS, although a small number are also written for Linus and Unix systems. Worms today work in the same basic way as 1988's Internet Worm: they scan the network for computers with vulnerable network services, break in to those computers, and copy themselves over. Worm outbreaks have become a cyclical plague for both home users and businesses, eclipsed recently in terms of damage by spyware.