IMAGINATIONS WELCOME

At DTG Internet services located in downtown Hartford, CT, virus erradication is a specialty that DTG has a very high “save” ratio.

“We are servicing more and more computer systems each day” explains Mark Ambrose, President of DTG Internet services.

“We see a lot of computers with multiple pop-up windows, strange warnings that your virus software has expired and of course virus programs that have really expired” explains Mark Ambrose.

We can get pickup your computer from your business or residence and get it right on the bench for an evaluation.

Lets get down to the basics about those darn computer viruses.

Computer Virus Basics

A computer virus is created when a programmer creates computer code that has the capability to replicate itself, hide, watch for a certain event to occur, and/or deliver a destructive or prankish payload on a disk or in a computer program. Viruses can attach themselves to just about any type of file and are spread as infected files are used by other computers. Some viruses are relatively harmless, while others are very devastating. They can destroy files, software, program applications, and cause the loss of data.

New computer viruses are constantly being created by malicious programmers. Because of this, it is vital to keep anti-virus software on computers up-to-date. Some anti-virus software programs allow users to set them to silently check for updates whenever users are connected to the Internet. Others remind users to periodically check for updates.

Worms and Trojans are closely related to viruses. A worm makes copies of itself on a computer, rather than infecting other files like viruses. A Trojan is a program that secretly installs itself on a computer and opens a back door to the computer so that malicious attacks can be remotely controlled. The actual Trojan is usually not damaging at first, but it is usually accompanied by other damaging programs.

To protect your home computer against computer viruses, worms, and trojans, you should invest in anti-virus software, such as the software offered by Norton or McAfee. You should also make sure it stays up-to-date. Virus protection software on school computers is regularly updated by the school system network technicians.

What Computer Viruses Infect

Viruses can enter computers in many ways. Once a virus has entered a system, it will generally hide until it is unknowingly run by the user. A virus will not act until it has been run or some pre-established condition has been met, such as a specific date. The effects of a virus may not be noticed for some time after it has infected a computer.

Viruses can infect several components of a computer’s operating and file system including:

• System Sectors/Boot Records – Viruses can infect the parts of the system that are used to run programs and perform functions such as start up and shut down.
• Files – Viruses can infect program files. These viruses stick to program files such as .com, .exe, .sys, etc. Some viruses hide in the memory of the computer at first, while others simply attack a specific software program, such as Microsoft Word.
• Companion Files – Viruses can create companion files that are a special type of file that adds files that run on the hard disk.
• Macros – Viruses can infect macro or data files.
• Disk Clusters – Viruses can infect files through the disk directory.
• Batch Files – Viruses can use batch files to infect a computer.
• Source Code – Viruses can be in additional code that is added to actual program source code.
• Visual Basic Worms – These worms use the Visual Basic programming language to control a computer and perform tasks.

Types of Computer Viruses

Viruses are categorized by how they infect computers. Some viruses fall into more than one of these categories.

Types of viruses include:

• Polymorphic Viruses – Polymorphic viruses change characteristics as they infect a computer.
• Stealth Viruses - Stealth viruses actively try to hide themselves from anti-virus and system software.
• Fast and Slow Infectors - Fast and Slow viruses infect a computer in a particular way to try to avoid being detected by anti-virus software.
• Sparse Infectors – Sparse Infectors don’t infect very often.
• Armored Viruses – Armored viruses are programmed to make eradication difficult.
• Multipartite Viruses – Multipartite Viruses are viruses that may fall into more than one of these categories.
• Cavity (Spacefiller) Viruses – Cavity (Spacefiller) viruses attempt to maintain a constant file size when infecting a computer in order to try to avoid detection.
• Tunneling Viruses – Tunneling viruses try to “tunnel” under anti-virus software while infecting.
• Camouflage Viruses – Camouflage viruses attempt to appear as a benign program.
• Virus Droppers – Virus Droppers are a special category of programs that place viruses on computers but are not by themselves an actual virus.

Ways to Catch a Computer Virus

There are several ways to catch a computer virus:

• From Floppy Disks – Be very careful about putting a floppy disk that has been in another computer in your computer, even if it is from a trusted source.
• From the Internet – Viruses can be attached to various types of Internet files, such as graphics and program files that people download from the Internet. Just browsing the Internet does not put your computer at risk. You have to download and install a file for a virus to be able to infect a computer.
• From E-Mail - Viruses often travel via e-mail attachments. E-mail messages by themselves do not carry viruses. Only .exe, .com or other types of executable files can carry a virus.
• From a Computer Network – Computer Networks are groups of computers linked together by a large computer called a server. The server and these computers constantly share information. If one file that is used by several network users becomes infected with a virus, the virus will quickly spread to the other users.

Symptoms of a Computer Virus

The following are some possible indications that a computer has been infected by a virus. These problems can also be caused by non-virus problems, but they are the most reported symptoms of a computer virus infection.

• Computer programs take longer to load than normal.
• The computer’s hard drive constantly runs out of free space.
• The floppy disk drive or hard drive runs when you are not using it.
• New files keep appearing on the system and you don’t know where they came from.
• Strange sounds or beeping noises come from the computer or keyboard.
• Strange graphics are displayed on your computer monitor.
• Files have strange names you don’t recognize.
• You are unable to access the hard drive when booting from the floppy drive.
• Program sizes keep changing.
• Conventional memory is less than it used to be and you can’t explain it.
• Programs act erratically.

If You Get a Computer Virus

At school:

• If you are on a school computer, contact your school tech leader or submit a request to computer support, immediately.

At home:

• If you do not have an anti-virus program, get one immediately. Many anti-virus programs can be downloaded from the Internet.
• Install the latest virus updates available for your anti-virus software. (Generally, you can get these updates at the anti-virus program web site.) Then run the anti-virus software to identify the virus. Most software will ask users to choose whether to clean the virus, delete the file, or ignore it when a virus is found.
• After getting rid of a virus, run your anti-virus software again to make sure the virus has been eradicated.
• Find an Internet web site that contains descriptions of viruses and search for information about the virus you have found on your computer.
• If you get an e-mail virus, contact everyone in your address book and tell them to be on the lookout for suspicious e-mails and attachments. Do not send any e-mails until you are sure the virus has been cleaned from your computer.

Safe Computing Practices

There are several things you can do the help protect your computer against viruses:

• Anti-Virus Software – If you don’t have an anti-virus software program, invest in one.
• Scan Your Computer on a Regular Basis – Scan you system with anti-virus software regularly.
• Update Your Anti-Virus Software on a Regular Basis – Keep your anti-virus software up to date. Do this at least weekly and more often if there are news reports of a new virus threat.
• Backup – Backup your files on a regular basis. Always maintain copies of files you can’t do without, just in case your computer gets infected and crashes.
• Turn off E-Mail Preview – Turn off the preview function if your e-mail software has one.
• Scan Floppy Disks – Scan floppy disks from other computers with anti-virus software before you use the disk. Simply place the disk in your floppy drive and run the anti-virus software program. If a virus is found, most programs will give you several choices about what to do, such as removing the virus, doing nothing, or deleting the file that contains the virus.
• Protect Your Floppy Disks – Write-protect any floppy disk you place into another computer. If the other computer has a boot sector virus, the write-protect on the disk will prevent it from becoming infected with the virus.
• Scan Downloaded Files – Scan downloaded Internet files with anti-virus software before you use or run them.
• Scan All E-Mail Attachments – If you receive an attachment you need to view, scan it with anti-virus software before you open it.
• Beware of E-Mail Attachments from Unknown Sources – If you receive an unexpected attachment from an unknown source, delete it. Never open attachments for files that end in .vbs (Visual Basic Script) or .js (Java Script). Viruses often travel in these types of files.
• Be Alert – Pay attention to news about virus alerts. You might want to subscribe to a virus alert e-mail notice from one of the anti-virus software makers.