Trojan horse

Trojan horse

The term comes from the a Greek story of the Trojan War, in which the Greeks give a giant wooden horse to their foes, the Trojans, ostensibly as a peace offering. But after the Trojans drag the horse inside their city walls, Greek soldiers sneak out of the horse's hollow belly and open the city gates, allowing their compatriots to pour in and capture Troy.

A destructive program that masquerades as a benign application. Unlike viruses, Trojan horses do not replicate themselves but they can be just as destructive. One of the most insidious types of Trojan horse is a program that claims to rid your computer of viruses but instead introduces viruses onto your computer.

The seven main types of Trojan horses are:

* Remote Access Trojans
* Data Sending Trojans
* Destructive Trojans
* Proxy Trojans
* FTP Trojans
* security software disabler Trojans
* denial-of-service attack (DoS) Trojans

For example, you download what appears to be a movie or music file, but when you click on it, you unleash a dangerous program that erases your disk, sends your credit card numbers and passwords to a stranger, or lets that stranger hijack your computer to commit illegal denial of service attacks.

Measures:-

1.Disconnect your computer from the Internet

Depending on what type of Trojan horse or virus you have, intruders may have access to your personal information and may even be using your computer to attack other computers. You can stop this activity by turning off your Internet connection. The best way to accomplish this is to physically disconnect your cable or phone line, but you can also simply "disable" your network connection.

2. Back up your important files

At this point it is a good idea to take the time to back up your files. If possible, compile all of your photos, documents, Internet favorites, etc., and burn them onto a CD or save them to some other external storage device. It is vital to note that these files cannot be trusted since they are still potentially infected.

3. Install an anti-virus program and scan your machine

Since your computer is infected with an unknown malicious program, it is safest to install an anti-virus program from an uncontaminated source such as a CD-ROM. You will have to visit your local computer or electronics store to a purchase the software. There are many to choose from, but all of them should provide the tools you need.

After you install the software, complete a scan of your machine. The initial scan will hopefully identify the malicious program(s). Ideally, the anti-virus program will even offer to remove the malicious files from your computer; follow the advice or instructions you are given.

If the anti-virus software successfully locates and removes the malicious files, be sure to follow the precautionary steps in Step 7 to prevent another infection. In the unfortunate event that the anti-virus software cannot locate or remove the malicious program, you will have to follow the next steps.
4. Reinstall your operating system
If the previous step failed to clean your computer, the only available option is to reinstall the operating system. Although this corrective action will also result in the loss of all your programs and files, it is the only way to ensure your computer is free from backdoors and intruder modifications. Before conducting the reinstall, make a note of all your programs and settings so that you can return your computer to its original condition.

It is vital that you also reinstall your anti-virus software and apply any patches that may be available.

5. Restore your files

If you made a back up CD in Step 3, you can now restore your files. Before placing the files back in directories on your computer, you should scan them with your anti-virus software to ensure they are not infected.

6. Protect your computer

To prevent future infections, you should take the following precautions:

• Do not open unsolicited attachments in email messages.

• Do not follow unsolicited links.

• Maintain updated anti-virus software.

• Use an Internet firewall.

• Keep your system patched.