Unfortunately, many users fall foul, and become vistoms, of viruses, worms, or Trojans. If your computer gets infected with malicious code, there are steps you can take to recover.
How do you know your computer is infected?
Unfortunately, there is no particular method to identify that your computer has been infected with malicious code. Some infections may completely destroy files and shut down your computer, while others may only subtly affect your computer's normal operations.
Be aware of any unusual or unexpected behaviors. If you are running anti-virus software, it may alert you that it has found malicious code on your computer. The anti-virus software may also be able to clean the malicious code automatically, but if it can't, you will need to take additional steps.
What can you do if you are infected?
- Minimize the damage
If you are at work and have access to an IT department, contact them immediately. The sooner they can investigate and clean your computer, the less damage to your computer and other computers running on the network.
If you are on your home computer or on a laptop, disconnect your computer from the internet. By removing the internet connection, you prevent an attacker or virus from being able to access your computer and perform tasks such as locating personal data, manipulating or deleting files, or using your computer to attack other computers.
- Remove the malicious code
If you have anti-virus software installed on your computer, update the virus definitions (if possible), and perform a manual scan of your entire system. If you do not have anti-virus software, you can purchase it at a local computer store.
If the software can't locate and remove the infection, you may need to reinstall your operating system, usually with a system restore disk that will have been supplied with your computer when you purchased it.
Note that reinstalling or restoring the operating system will normally erase all of your files and any additional software that you have installed on your computer.
After reinstalling the operating system and any other software that you required, be sure to install all of the appropriate patches to fix known vulnerabilities.
How can you reduce the risk of another infection?
Dealing with the presence of malicious code on your computer can be a frustrating experience that can cost you time, money, and data. The following recommendations will build your defense against future infections:
- Use and maintain anti-virus software
Anti-virus software recognizes and protects your computer against most known viruses. However, attackers are continually writing new viruses, so it is important to keep your anti-virus software current.
- Change your passwords
Your original passwords may have been compromised during the infection, so you should change them. This includes passwords for web sites that may have been cached in your browser. Make the passwords difficult for attackers to guess.
- Keep software up-to-date
Install software patches so that attackers can't take advantage of known problems or vulnerabilities. Many operating systems offer automatic updates. If this option is available, you should enable it.
- Install or enable a firewall
Firewalls may be able to prevent some types of infection by blocking malicious traffic before it can enter your computer. Some operating systems actually include a firewall, but you need to make sure it is enabled.
- Use anti-spyware tools
Spyware is a common source of viruses, but you can minimize the number of infections by using a legitimate program that identifies and removes spyware.
- Follow good security practices
Take appropriate precautions when using email and web browsers so that you reduce the risk that your actions will trigger an infection.
As a precaution, you should always maintain backups of your files on CDs or DVDs so that you have saved copies if you do get infected again.