Virus Info Center -Glossary

ActiveX malicious code		Aliases
Boot sector viruses		Date of origin
Description		Destructive viruses
Encrypted viruses		File infecting viruses
In-The-Wild virus list		Java malicious code
Joke programs		Language
Malware		Macro virus
Password		Payload
Place of origin		Platform
Risk rating		Size of macro/malicious code/virus
Script viruses (VBScript, JavaScript, HTML)		Solution
Technical details		Trigger condition or date
Trojan		Virus types
Worm

ActiveX malicious code 
ActiveX controls allow web developers to create interactive, dynamic web pages such as HouseCall, Trend Micro's free on-line scanner. An ActiveX control is embedded into a web page, and runs automatically when the page is viewed. Crackers, virus writers and others who wish to cause mischief, or worse, may use malicious ActiveX code as a vehicle to attack your system. In many cases, by changing a web browser's security settings to "high", these ActiveX controls can be contained. To remove malicious ActiveX controls, all you just have to do is delete them.

Aliases
A single virus may be known by several names, or aliases. There is no commonly accepted industry standard for naming viruses and malicious mobile code. See virus types for an explanation of Trend Micro virus naming conventions.

Boot sector viruses
Boot sector viruses infect one of two areas of a floppy disk; either the boot sector or the partition table. Computer systems are most likely to be attacked by boot sector viruses when you use an infected floppy disk to boot the system -- in which case, even a failed boot attempt can infect the hard drive. Also, there are a few viruses that can infect the boot sector from usable programs. These are known as multi-partite viruses. Once a computer is infected, the boot sector virus will attempt to infect every diskette that is used in that computer. Generally, boot sector viruses can be successfully removed.

Date of origin
Indicates when a virus was first discovered (if known).

Description
This is a brief explanation of a virus listed in the Trend Virus Encyclopedia. For detailed technical information, click on the "Tech Details" tab.

Destructive viruses
In addition to self-replication, computer viruses may be designed to damage your system, by corrupting or deleting files, formatting your hard drive, committing denial-of-service attacks, etc.

Encrypted viruses
This description indicates that the virus is written in such a way that average antivirus software are unable to detect it. Trend Micro antivirus products, however, are able to detect such viruses.

File infecting viruses
File infecting viruses infect certain commonly-used programs (generally, files that have ".com" or ".exe" extensions). Most of these types of viruses simply try to replicate and spread by infecting other host programs. However, some inadvertently destroy the program they infect by changing how the program originally worked. A minority of file-infecting viruses are very destructive, attempting to format the hard drive at a pre-determined time or to perform other malicious acts. In many cases, a file-infecting virus can be successfully removed from the infected file. If the virus has changed the program, the original file will be unrecoverable.

In-The-Wild virus list
This is a list of the most common viruses that have been found worldwide. The list is compiled by renowned antivirus researcher Joe Wells. Wells updates the list regularly, working closely with antivirus research teams around the world, including Trend Micro. When ICSA (International Computer Security Association) conducts virus testing of antivirus products, the In-The-Wild virus list serves as the basis for its comparative analysis. More info: http://www.wildlist.org

Java malicious code
Java is a computer language that allows web developers to create interactive, dynamic web pages. Java applets are small, portable Java programs embedded into HTML pages. They run automatically when the pages are viewed. Crackers, virus writers and others who wish to cause mischief, or worse, may use Java malicious code as a vehicle to attack the system. In many cases, a "high" web browser security setting can prevent this kind of infection..

Joke programs
Joke programs are not really viruses. They do not self-replicate. They are added to the detection list because they have been known to be very annoying and/or contain pornographic images. Joke programs cannot spread unless someone deliberately distributes them. To get rid of a Joke program, delete the file from your system.

Language
This refers to the language locale of the platform where the virus is designed to run, such as Microsoft Word in English or Chinese.

Malware
Malware is a general term used to refer to any unwanted or malicious programs or mobile code, such as viruses, Trojans, worms and Joke programs.

Macro virus
Macro viruses use the macro programming language of an application to distribute themselves. They infect documents such as Microsoft Word or Excel. Unlike other viruses, macro viruses do not infect programs or boot sectors - although a few do drop programs on the user's hard drive. The dropped files may then infect commonly used programs or boot sectors. Macro viruses can be removed from the infected document using Trend Micro's antivirus products.

Password
Some viruses set a password when they infect a document. The main objective of the virus here is to make the document inaccessible to the computer user. The password can be a word, phrase or even a randomly generated number.

Payload
A payload is an action a virus performs on the infected computer. This can be something relatively harmless like showing messages or ejecting the CD from the CD drive, or something destructive like deleting the entire hard drive.

Place of origin
Indicates where a virus is believed to have originated (if known).

Platform
Indicates the operating system or application on which a virus can run and perform an infection. The platform for executable viruses is generally a particular operating system, while for macro viruses its a specific application.

Risk rating
The risk rating of a virus is an assessment of the threat it poses. It is based on a number of different factors including, but not limited to, the virus' potential to spread, its destructiveness, the actual number of cases reported, etc.

Size of macro/malicious code/virus
Indicates the size of the virus code in bytes. This number is sometimes used as part of the virus name to distinguish it from its variants.

Script viruses (VBScript, JavaScript, HTML)
Script viruses are written in script programming languages, such as VBScript (Visual Basic Script) and JavaScript. Viruses made with either of these two scripts use Microsoft's Windows Scripting Host (WHS) to activate themselves and infect other files. Since WHS is available on Windows 98 and Windows 2000, the viruses can be activated simply by double-clicking a malicious *.vbs or *.js file in Windows Explorer.

HTML viruses use the scripts within HTML files to do their damage. These embedded scripts automatically come to life the moment the HTML page is viewed from a script-enabled browser.

Solution
Most viruses can be cleaned or removed from the infected host files by Trend Micro's antivirus software. Special removal instructions are provided for viruses or Trojans that modify the system registry and/or drop files. Generally, to remove Trojans or joke programs, you just need to delete the program files - no cleaning action is needed.

Technical details
The "technical details" section of a Virus Encyclopedia profile contains specific information about the actions performed by a virus on the host system. This information is provided to assist system administrators and users in identifying and removing viruses. 

Trigger condition or date
This indicates the condition or date on which the virus will be triggered. Please note that the virus may move into your computer on any day of the year. Without proper antivirus protection, you won't know the virus is in there until it is too late - the date the virus reveals itself, doing whatever damage it was designed to do.

Trojan
A Trojan or Trojan horse is a form of malware that disguises itself as a legitimate program. It performs unexpected or unauthorized - usually malicious - actions, such as displaying messages, erasing files or formatting disks. A Trojan horse doesn't infect other host files, thus cleaning is not necessary. To get rid of a Trojan, simply delete the program.

Virus types
Viruses and other malware are classified into various types depending on their file formats and infection routines. To distinguish among these types, Trend Micro uses the following prefixes:

Worm
A computer worm is a self-contained program (or set of programs) that is able to spread functional copies of itself or its segments to other computer systems. The propagation usually takes place via network connections or email attachments. To get rid of a worm, simply delete the program.