Programs that facilitate delivery of advertising content to the user through their own window, or by utilizing another program's interface. In some cases, these programs may gather information from the user's computer, including information related to Internet browser usage or other computing habits, and relay this information back to a remote computer or other location in cyber-space.
Adware can be downloaded from Web sites (typically in shareware or freeware), email messages, and instant messengers. Additionally, a user may unknowingly receive and/or trigger adware by accepting an End User License Agreement from a software program linked to the adware or from visiting a website that downloads the adware with or without an End User License Agreement.
Programs that use a computer or modem to dial out to a 900 number or FTP site, typically to accrue charges. Dialers can be installed with or without a user's explicit knowledge, and may perform their dialing activity without a user's specific consent prior to dialing.
Tools that can be used by a hacker or unauthorized user to attack, gain unwelcome access to or perform identification or fingerprinting of your computer. While some hack tools may also be valid for legitimate purposes, their ability to facilitate unwanted access makes them a threat. Hack tools also generally:
o Attempt to gain information on or access hosts surreptitiously, utilizing methods that circumvent or bypass obvious security mechanisms inherent to the system it is installed on, and/or
o Facilitate an attempt at disabling a target computer, preventing its normal use
One example of a hack tool is a keystroke logger -- a program that tracks and records individual keystrokes and can send this information back to the hacker. Also applies to programs that facilitate attacks on third-party computers as part of a direct or distributed denial-of-service attempt.
Usually an email that gets mailed in chain letter fashion describing some devastating, highly unlikely type of virus. Hoaxes are detectable as having no file attachment, no reference to a third party who can validate the claim, and by the general tone of the message.
Programs that alter or interrupt the normal behavior of your computer, creating a general distraction or nuisance. Joke programs generally do not themselves engage in the practice of gathering or distributing information from the user's computer.
Programs that allow one computer to access another computer (or facilitate such access) without explicit authorization when an access attempt is made. Once access is gained, usually over the Internet or by direct dial access, the remote access program can attack or alter the other computer. It may also have the ability to gather personal information, or infect or delete files. They may also create the risk that third party programs can exploit its presence to obtain access. Such remote access programs generally:
o Attempt to remain unnoticed, either by actively hiding or simply not making their presence on a system known to the user, and/or
o Attempt to hide any evidence of their being accessed remotely over a network or Internet
Means by which these programs provide access may include notifying a remote host of the machine by sending its address or location, or employing functionality that wholly or partially automates access to the computer on which the program is installed.
Threats that do not meet the definitions of Viruses, Trojan horses, Worms, or other expanded threat categories, but which may present a threat to a computer and its data, an unwanted nuisance to the user, or exhibit other unexpected or unwanted results when the threat is present and functioning. This category includes programs that encrypt or otherwise attempt to obfuscate some of their functionality, making it difficult to determine whether they fall into one of the other categories.
Programs that have the ability to scan systems or monitor activity and relay information to other computers or locations in cyber-space. Among the information that may be actively or passively gathered and disseminated by Spyware: passwords, log-in details, account numbers, personal information, individual files or other personal documents. Spyware may also gather and distribute information related to the user's computer, applications running on the computer, Internet browser usage or other computing habits.
Spyware frequently attempts to remain unnoticed, either by actively hiding or by simply not making its presence on a system known to the user. Spyware can be downloaded from Web sites (typically in shareware or freeware), email messages, and instant messengers. Additionally, a user may unknowingly receive and/or trigger spyware by accepting an End User License Agreement from a software program linked to the spyware or from visiting a website that downloads the spyware with or without an End User License Agreement.
A Trojan Horse portrays itself as something other than what it is at the point of execution. While it may advertise its activity after launching, this information is not apparent to the user beforehand. A Trojan Horse neither replicates nor copies itself, but causes damage or compromises the security of the computer. A Trojan Horse must be sent by someone or carried by another program and may arrive in the form of a joke program or software of some sort. The malicious functionality of a Trojan Horse may be anything undesirable for a computer user, including data destruction or compromising a system by providing a means for another computer to gain access, thus bypassing normal access controls.
A virus is a program or code that replicates itself onto other files with which it comes in contact; that is, a virus can infect another program, boot sector, partition sector, or a document that supports macros, by inserting itself or attaching itself to that medium. Most viruses only replicate, though many can do damage to a computer system or a user's data as well.
A worm is a program that makes and facilitates the distribution of copies of itself; for example, from one disk drive to another, or by copying itself using email or another transport mechanism. The worm may do damage and compromise the security of the computer. It may arrive via exploitation of a system vulnerability or by clicking on an infected e-mail.