Macro viruses spread from applications which use macros. The macro viruses which are receiving attention currently are specific to Word 6, WordBasic and Excel. However, many applications, not all of them Windows applications, have potentially damaging and infective macro capabilities too.
A CAP macro virus, now widespread, infects macros attached to Word 6.0 for Windows, Word 6.0.1 for Macintosh, Word 6.0 for Windows NT, and Word for Windows 95 documents.
What makes such a virus possible is that the macros are created by WordBASIC and even allows DOS commands to be run. WordBASIC in a program language which links features used in Word to macros.
A virus, named "Concept," has no destructive payload; it merely spreads, after a document containing the virus is opened. Concept copies itself to other documents when they are saved, without affecting the contents of documents. Since then, however, other macro viruses have been discovered, and some of them contain destructive routines.
Microsoft suggests opening files without macros to prevent macro viruses from spreading, unless the user can verify that the macros contained in the document will not cause damage. This does NOT work for all macro viruses.
Why are macro viruses so successful? Today people share so much data, email documents and use the Internet to get programs and documents. Macros are also very easy to write. The problem is also that Word for Windows corrupts macros inadvertently creating new macro viruses.
3.Ways Computer Viruses Are Spread
It is the worst nightmare of every computer user: you wake up one day and realize that you have a virus, and you don’t know quite how to get rid of it. Most people these days understand what a virus is and how harmful it can be, but they are still somewhat unsure how computer viruses spread. The truth is that there are dozens of different ways in which a virus can spread from computer to computer, but let’s take a look at the most frequent ways in which people run into viruses, spyware and Trojans on the Internet. 1. Email attachments. The world became familiar with the phenomena of email attachments carrying viruses thanks to Microsoft’s Outlook Express automatically opening every attachment to every email you received a few years back. Now that email clients no longer do this, the infection rate from email attachments is significantly lower, but it can still be a common problem. The golden rule is that if you don’t know what an attachment is, don’t open it. To this day, many email users never open attachments, no matter what. You don’t have to take such drastic steps to protect yourself, however; simply use common sense when opening attachments in your email. 2. Rogue Websites. It is depressing to know that you may become infected with spyware or a virus by doing nothing more than simply visiting a website, but it is true. Many adult websites, gambling websites and other less than trustworthy websites will attempt to automatically access your computer when you visit them. They often install adware bugs that will cause a flurry of pop ups to appear on your screen. This adware will often allow for other programs with even more nefarious purposes to be installed and before you know it, your computer will be swamped. To stop these rogue websites, adjust the settings on your antivirus software and firewall so that no outside connections can be made and no programs can be installed without your express permission. 3. Networks. If your computer is connected to a home network or if your work computer is part of a larger network, you may find yourself with an infection through no fault of your own. Someone else on the network downloaded a bug by accident, and within minutes, the entire network could be infected. There isn’t much you can do to stop these kinds of infections, short of having your network administrator ensure that everyone’s antivirus software is up to date so that the invading bug can be removed as quickly as possible. 4. Infected Boot disks. Now that hard drives are obscenely large, the overwhelming percentage of us don’t bother to use boot disks anymore, but a virus can still be spread if an infected disk is in your hard drive and you attempt to restart. When you start your computer, your machine will always check your drives to see if a disk with boot information is present. If one is, your computer will likely automatically attempt to boot from the disk and not from your drive. If a virus is present, it will often be activated and you will become infected. Always know the origin of any disk you put into your drive. 5. Phishing Schemes. Learning how computer viruses spread is important to keep yourself, and your personal information, safe online. Phishing schemes are one of the chief ways in which people end up with their identity stolen and a computer fill of viruses. A phishing scheme starts when you receive an email from a website claiming to be your bank or credit card company. You are asked to click a link and log in, but the truth is that you’ve just given away all of your personal information. Often times, when you visit these sites, spyware, adware and viruses are automatically installed on your computer (see Rogue Websites, above). Your lender or credit card will often send out a real notice that let’s you know that a phishing scheme is going around. The smartest thing you can do is to simply call your bank or credit card company if you receive an email saying there is a problem with your account instead of blindly following links in your email. 6. Infected Software. One of the great things about the Internet is how many free games and programs there are out there, but these free programs often come at a price. Too many rogue websites intentionally infect their freeware (like Kazaa) with trojan viruses so that you unknowingly infect your computer every time you download a free game or piece of software. The key here is to only download freeware or shareware from a trusted source like CNet that always ensures your safety. 7. Hackers. The Internet today is a much more law abiding place than it was ten years ago. Not only did most people not have antivirus protection and firewalls that could stop incoming attacks, most people didn’t even know what they were. Today, people understand the value of good online protection, but hackers can still pose a problem if you allow your protection software to lapse. The best way to beat hackers is to ensure that you have a firewall and up to date antivirus software. 8. Instant Messaging. It is difficult to find a computer in this day and age that doesn’t have at least one instant messaging service installed on it. Unfortunately, these programs are often targets of hackers who see an easy way to trick people into clicking links that lead them to rogue websites. Common sense can keep you out of trouble, however. Only chat with people you know and never follow links to sites that you don’t recognize. You should easily be able to keep Internet worms, viruses and other bugs at bay. 9. From Mobile Devices. A recent story in the newspaper should serve as a wake up call for anyone who is getting ready to plug in a mobile device into their computer for the first time. A family purchased a digital picture frame from a local store and when they attempted to install the software that came with it, they inadvertently infected their computer with a virus. There really is no way to stop such an infection from happening, since we all buy peripherals that work with our computer, but we can ensure that we have the tools ready to go if an infection should happen. Keep your anti virus software up to date at all times and you should be able to wrestle control back from any Internet bug. 10. Friends and Relatives. Often times, we are sent viruses through our email from people that we know and trust. The social networking site Facebook has had to battle this very problem when their serves get a bug and automatically send out emails to everyone on the system that are infected. Often times, these emails are extremely generic sounding and come with suspicious attachments, but people often open them anyway since they have come from a friend or from a site they trust, like Facebook. Remember, if you get an attachment with an .exe extension or a .dll, don’t ever open it.
4. How do I prevent a virus?
1. Load only software from original disks or CD's. Pirated or copied software is always a risk for a virus.
2. Execute only programs of which you are familiar as to their origin. Programs sent by email should always be suspicious.
3. Computer uploads and "system configuration" changes should always be performed by the person who is responsible for the computer.
4. Password protection should be employed.
5. Check all shareware and free programs downloaded from on-line services with a virus checking program.
6. Purchase or download a anti-virus program that runs as you boot or work your computer. Up-date it frequently. There are free anti-virus programs availible.
