About viruses, worms and Trojan Horses

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About viruses, worms and Trojan Horses

About viruses and worms

A virus is a program that’s capable of continually replicating with little or no user intervention. There’s typically a piece of code that causes an unexpected and usually malicious event (or “payload”) to occur. Viruses are often disguised as games or images with clever, inviting titles such as "Pictures of ME".

A worm is a virus that spreads by creating duplicates of itself on other drives, systems or networks. Worms may send copies of themselves to other computers across network connections, through email, through an infected Web page or through instant messages and Internet Relay Chat (IRC). Some worms are differentiated as being "@m" or "@mm", which signifies that their primary distribution method is through electronic mail or mass-mail.

About Trojan horses

A Trojan horse is a program that either pretends to have, or is described as having, a set of useful or desirable features but actually contains a damaging payload. True Trojan horses are not technically viruses, since they do not replicate; however, many viruses and worms use Trojan horse tactics to initially infiltrate a system. Although Trojans are not technically viruses, they can be just as destructive.

Many people use the term "Trojan" to refer only to non-replicating malicious programs, thus making a distinction between Trojans and viruses.

Virus hoaxes

There are a lot of viruses out there; however, some aren't really out there at all. Virus hoaxes are more than mere annoyances. They may lead some users to routinely ignore all virus warning messages, leaving them vulnerable to a genuine, destructive virus.

Next time you receive an urgent virus warning message be sure to check the list of known virus hoaxes. A common hoax is the Jdbgmgr.exe hoax. It describes an otherwise legitimate system file as being a virus that is not detected by McAfee or Norton. It hibernates in your computer system for 14 days before blowing your computer to smithereens. The file is displayed with a teddy bear icon, as shown below, and is often convincing as a result.

Remember to never open an email attachment unless you know what it is -- even if it's from someone you know and trust.

Common Hoax email Phrases:

  • [email virus hoax name here], do not open it!
  • Delete it immediately! It contains the [hoax name] virus.
  • 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! (Remember that virus writers can use known hoaxes to their advantage. For example, AOL4FREE began as a hoax virus warning. Then somebody distributed a destructive Trojan attached to the original hoax virus warning.)
  • Always remain vigilant.
  • Never open a suspicious attachment.

Not All Computer Problems Are Virus Related

Nowadays, it’s easy to blame any computer problem on a virus. Listed below is a list of common problems NOT caused by a virus or other malicious code:

  • Hardware problems. There are no viruses that can physically damage computer hardware, such as chips, boards and monitors.
  • The computer beeps at startup with no screen display. This is usually caused by a hardware problem during the boot process. Check your computer documentation for the meaning of the beep codes.
  • The computer does not register 640K of conventional memory. This can be a sign of a virus, but it is not conclusive. Some hardware drivers such as those for the monitor or SCSI card can use some of this memory. Consult with your computer manufacturer or hardware vendor to determine if this is the case.
  • You have two antivirus programs installed and one of them reports a virus. While this could be a virus, it can also be caused by one antivirus program detecting the other program's signatures in memory.
  • You are using Microsoft Word and it warns you that a document contains a macro. This does not mean that the macro is a virus.
  • You are not able to open a particular document. This is not necessarily an indication of a virus. Try opening another document or a backup of the document in question. If other documents open correctly, the document may be damaged.
  • The label on a hard drive has changed. Every disk is allowed to have a label. You can assign a label to a disk by using the DOS Label command.

AOL now offers Virus Removal services for as low as $39.99 (or it may be included in your existing plan - click here to see if you're eligible). Call 1-855-288-1686 and let one of our expert technicians access your computer from a remote location to identify and remove viruses or malware.

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Last updated: 10-18-2013
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