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ActiveX malicious code
ActiveX controls allow Web developers to
create interactive, dynamic Web pages with broader functionality such as
HouseCall, Cyber Sentry's free on-line scanner. An ActiveX control is a
component object embedded in a Web page which runs automatically when the
page is viewed. In many cases, the Web browser can be configured so that
these ActiveX controls do not execute by changing the browser's security
settings to "high." However, hackers, virus writers, and others
who wish to cause mischief or worse may use ActiveX malicious code as a
vehicle to attack the system. To remove malicious ActiveX controls, you
just need to delete them.
Aliases
There is no commonly accepted
industry standard for naming viruses and malicious mobile code. Each may
be known by several different names or aliases. See virus
types for an explanation of Cyber Sentry's virus-naming conventions.
Boot
sector viruses
Boot sector viruses infect the boot
sector or partition table of a disk. Computer systems are most likely to
be attacked by boot sector viruses when you boot the system with an
infected disk from the floppy drive - the boot attempt does not have to be
successful for the virus to infect the hard drive. Also, there are a few
viruses that can infect the boot sector from executable programs- these
are known as multi-partite viruses and they are relatively rare. Once the
system is infected, the boot sector virus will attempt to infect every
disk that is accessed by that computer. In general, boot sector viruses
can be successfully removed.
Destructive
viruses
In addition to self-replication, computer viruses may have a routine that
can deliver the virus payload. A
virus is defined as destructive if its payload does some damage to your
system, such as corrupting or deleting files, formatting your hard drive,
and committing denial-of-service attacks etc.
ELF
ELF refers to Executable and Link Format, which is the well-documented and
available file format for Linux/UNIX executables. Cyber Sentry's products
detect malicious code for Linux/UNIX as "ELF_Virusname."
Encrypted
viruses
Indicates that the virus code contains a special routine that encrypts the
virus body to evade detection by antivirus software. Cyber Sentry’s
antivirus products have the ability to decrypt the virus body and detect
such viruses.
File
infecting viruses
File infecting viruses infect executable programs (generally, files that
have extensions of .com or .exe). Most such viruses simply try to
replicate and spread by infecting other host programs - but some
inadvertently destroy the program they infect by overwriting some of the
original code. There is a minority of these viruses that are very
destructive and attempt to format the hard drive at a pre-determined time
or perform some other malicious action. In many cases, a file-infecting
virus can be successfully removed from the infected file. If the
virus has overwritten part of the program's code, the original file will
be unrecoverable.
In-the-Wild
virus list
The In-the-Wild virus list is a list of the most common viruses that have
been found infecting users’ computers worldwide. The list is compiled by
the renowned antivirus researcher Joe Wells. Wells updates the list
regularly, working closely with antivirus research teams around the world,
including Cyber Sentry. 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 applets allow Web developers to create interactive, dynamic Web pages
with broader functionality. Java applets are small, portable Java programs
embedded in HTML pages. They can run automatically when the pages are
viewed. However, hackers, virus writers, and others who wish to cause
mischief may use Java malicious code as a vehicle to attack the system. In
many cases, the Web browser can be configured so that these applets do not
execute by changing the browser's security settings to "high."
Joke
programs
Joke programs are ordinary executable programs. They are added to the
detection list because they are found to be very annoying and/or they
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 virus working platform such as
MS Word in English or Chinese.
Malware
Malware is a general term used to refer to any unexpected or malicious
programs or mobile codes such as viruses, Trojan, worm, or Joke programs.
Macro
virus
Macro viruses are viruses that use another application's macro programming
language to distribute themselves. They infect documents such as MS Word
or MS 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 infect executable programs or boot
sectors. Macro viruses can be removed safely from the infected document
while passing thro' the Cyber Sentry mail servers.
Special note: Occasionally, you may get an
"illegal operation" error when you try to start MS Word after
cleaning a Word macro virus. If this happens, search for the file
"normal.dot" and rename it to "normaldot.bak." MS Word
will generate a new, clean "normal.dot" the next time it is
started. This problem occurs because some viruses can leave harmless code
residue that MS Word may be reading incorrectly, causing erratic behavior.
Cyber Sentry's antivirus software only removes malicious viral code and not
user-created macros.
NE
NE refers to New Executable, which is the standard Windows 16-bit
executable file format. Windows 16-bit viruses are detected by Cyber Sentry
products as "NE_Virusname."
Password
Some viruses set a password when they infect a document. The main
objective of the virus here is to make the document inaccessible. This
password can be a word, phrase, or even a randomly generated number.
Payload
A virus’ payload is an action it performs on the infected computer. This
can be something relatively harmless like showing messages or ejecting the
CD drive, or something destructive like deleting the entire hard drive.
PE
PE refers to Portable Executable, which is the standard Win32 executable
file format. Windows 32-bit viruses are detected by Cyber Sentry products as
"PE_Virusname."
Platform
Indicates the computer operating system or application on which a virus
can run and perform an infection. Generally, a particular operating system
is required for executable viruses and a specific application is needed
for macro viruses.
Risk
rating
The risk rating of a virus is an assessment of the threat posed by a
virus. It is based on a number of different factors including, but
not limited to, potential to spread, destructiveness of the payload, and
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 and JavaScript. VBScript (Visual Basic Script) and JavaScript
viruses make use of Microsoft's Windows Scripting Host to activate
themselves and infect other files. Since Windows Scripting Host is
available on Windows 98 and Windows 2000, the viruses can be activated
simply by double-clicking the *.vbs or *.js file from Windows Explorer.
HTML viruses use the scripts embedded in
HTML files to do their damage. These embedded scripts automatically
execute the moment the HTML page is viewed from a script-enabled browser.
Trigger
condition or date
This is to indicate the condition or date on which the virus’ payload
will be triggered. Please note that date-activated viruses may infect your
computer 365 days a year. Your computer may be infected by these viruses
prior to the date specified.
Trojan
A Trojan horse is a program that performs some unexpected or unauthorized,
usually malicious, actions such as displaying messages, erasing files or
formatting a disk. 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, Cyber Sentry uses the following prefixes:
- ActiveX
malicious code - ATVX
- Boot
sector viruses - no prefix
- COM
and EXE file infectors - PE, NE,
or no prefix
- Executable
and Link format - ELF
- Joke
programs - JOKE
- Java
malicious code - JAVA
- Macro
viruses - W2KM, W97M, X97M, P97M, A97M, WM, XM, V5M
- Trojan
horses - TROJ
- VBScript,
JavaScript or HTML viruses - VBS, JS, HTML
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 you just need to
delete the program.
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