Glossary of  Viruses Etc.

Adware

Programs designed to launch advertisements, often pop-up banners, on host machines and/or to re-direct search engine results to promotional web sites. Adware programs are often built into freeware or shareware programs, where the adware forms an indirect ‘price’ for using the free program. Sometimes a Trojan silently downloads an adware program from a web site and installs it onto a user’s machine. (Trojan Droppers) Hacker tools, often referred to as Browser Hijackers (because they subvert the web browser to install a program without the user’s knowledge), download the adware program using a web browser vulnerability.

Browser Hijackers may change browser settings, re-direct incorrect or incomplete URLs, or change the default homepage. They may also re-direct searches to ‘pay-to-view’ (often pornographic) web sites.

 

Browser Hijacker

Browser Hijackers modify the user’s web browser settings. This may involve changing the default home page, re-directing searches to unwanted web sites, adding unwanted (sometimes pornographic) bookmarks or generating unwanted pop-up windows.

 

Backdoor Trojans

These are the most dangerous, and most widespread, type of Trojan. Backdoor Trojans provide the author or ‘master’ of the Trojan with remote ‘administration’ of victim machines. Unlike legitimate remote administration utilities, they install, launch and run invisibly, without the consent or knowledge of the user. Once installed, backdoor Trojans can be instructed to send, receive, execute and delete files, harvest confidential data from the computer, log activity on the computer and more.

 

Virus

Synonyms: Computer virus, Malicious program, Classic virus

Today the term virus is often loosely used to refer to any type of malicious program, or is used to describe anything bad that a malicious program does to a host system. Strictly speaking, however, a virus is defined as program code that replicates.

Of course, this simple definition leaves plenty of scope for further sub-division. Sometimes viruses are further classified by the types of object they infect. For example, boot sector viruses, file viruses, macro viruses.

Or they may be classified by the method they use to select their host. ‘Indirect action file viruses’ load into memory and hook into the system such that they can infect files as they are accessed. Conversely, ‘direct action file viruses’ do not go memory resident, simply infecting a file (or files) when an infected program is run and then ‘going to sleep’ until the next time an infected file is run.

 

Spyware

Synonyms: Potentially hostile programs, Malware-related programs

‘Spyware’ is something of a grey area, so there’s no copy-book definition for it. However, as the name suggests, it’s often loosely defined as software that is designed to gather data from a computer and forward it to a third party without the consent or knowledge of the computer’s owner. This includes monitoring key strokes, collecting confidential information (passwords, credit card numbers, PIN numbers, etc.), harvesting e-mail addresses or tracking browsing habits. There’s a further by-product, of course: such activities inevitably affect network performance, slowing down the system and thereby affecting the whole business process.

 

Malware

Synonyms: Malicious software

Malware (short for malicious software) refers to any program that is deliberately created to perform an unauthorized, often harmful, action.

 

Worm

Synonyms: Computer worm, Email worm, Internet worm, Network worm

Worms are generally considered to be a subset of viruses, but with key differences. A worm is a computer program that replicates, but does not infect other files: instead, it installs itself on a victim computer and then looks for a way to spread to other computers.

From a user’s perspective, there are observable differences. In the case of a virus, the longer it goes undetected, the more infected files there will be on the victim computer. In the case of a worm, by contrast, there is just a single instance of the worm code. Moreover, the worm’s code is ‘self-standing’, rather than being added to existing files on the disk.

 

PSW Trojans

Synonyms: Password-stealing Trojans

These Trojans are designed to steal passwords from the victim machine (although some steal other types of information also: IP address, registration details, e-mail client details, and so on). This information is then sent to an e-mail address coded into the body of the Trojan. The first PSW Trojans were AOL password stealing Trojans: and they are so numerous that they form a specific subset of PWS Trojans.

 

Kaspersky Internet Security has a dedicated site listing updates on all forms of viruses.

http://www.viruslist.com

 

TrendMicro  Internet Security has a similar information section

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