Rule Number One – Don’t trust anybody! Not even your friends!
Unfortunately, for anyone who uses a PC today, viruses are a fact of life, and measures must be taken on all systems to protect against all forms of virus activity. Due to widespread use of the Internet, email has become the most common mechanism for the spread of viruses. Many viruses now scan your address book, and automatically send themselves to all addresses. If your name appears in their address book, you will often automatically receive the virus. And so the Rule!
What is a Virus?
A computer virus is a small program written to alter the way a computer operates, without the permission or knowledge of the user. A virus must meet two criteria:
- It must execute itself. It will often place its own code in the path of execution of another program.
- It must replicate itself. For example, it may replace other executable files with a copy of the virus infected file. Viruses can infect desktop computers and network servers alike.
Some viruses are programmed to damage the computer by damaging programs, deleting files, or reformatting the hard disk. Others are not designed to do any damage, but simply to replicate themselves and make their presence known by presenting text, video, and audio messages. Even these benign viruses can create problems for the computer user. They typically take up computer memory used by legitimate programs. As a result, they often cause erratic behavior and can result in system crashes. In addition, many viruses are bug-ridden, and these bugs may lead to system crashes and data loss.
A trojan horse (or “trojan”) is simply a program that purports to do one thing but does something else that you do not know about. It has, so to speak, a public agenda that is harmless, and a private agenda that is not. One particular sub-category of trojans makes it possible for someone else to access your computer over the Internet. This is the category we are concerned with here. There are other types of trojans
Worms are programs that replicate themselves from system to system without the use of a host file. This is in contrast to viruses, which requires the spreading of an infected host file. Although worms generally exist inside of other files, often Word or Excel documents, there is a difference between how worms and viruses use the host file. Usually the worm will release a document that already has the “worm” macro inside the document. The entire document will travel from computer to computer, so the entire document should be considered the worm. PrettyPark.Worm is a particularly prevalent example.
Virus hoaxes are messages, almost always sent by email, that amount to little more than chain letters. Some of the common phrases used in these hoaxes are:
- If you receive an email titled [email virus hoax name here], do not open it!
- Delete it immediately!
- It will delete everything on your hard drive and [extreme and improbable danger specified here].
- This virus was announced today by [reputable organization name here].
- Forward this warning to everyone you know!
Most virus hoax warnings do not deviate far from this pattern. If you are unsure if a virus warning is legitimate or a hoax, assume it’s a hoax.
How Do I Protect Myself?
- Ensure you have current antivirus software installed & running in real-time scan mode.
- Update your virus definition files regularly – at least weekly. Many products will now do this automatically for you.
- Regularly (at least weekly) perform a full scan on your system.
- Ensure your applications have all the latest vendor security patches, particularly if you run Microsoft’s Word, Excel, Outlook or Outlook Express.
- Ensure that application security settings are at the highest possible level commensurate with your requirements.