Recover your PC from virus attack

Once you know that your machine is infected with a Trojan Horse or virus (or if your machine is exhibiting unexpected behavior and you suspect that something is wrong), then you need to perform certain tasks.
If you know what specific malicious program has infected your computer, you can visit one of several anti-virus web sites and download a removal tool.

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.

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 DVD 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.

Scan your machine
Since your computer (including its operating system) may be infected with a virus, it is safest to scan the machine from a live CD (or “rescue” CD) rather than a previously installed antivirus program. Many antivirus products provide this functionality. Another alternative is to use a web-based virus removal service, which some antivirus software vendors offer free virus scan.

Reinstall your operating system
If the previous step failed to clean your computer, the most effective option is to wipe or format the hard drive and 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.
Many computer vendors also offer a rescue partition or disc(s) that will do a factory restore of the system. Check your computer’s user manual to find out whether one of these is provided and how to run it.

Restore your files
If you made a backup your files, now 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 check them for known viruses.

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 Internet firewall software. 
• Secure your web browser. 
• Keep your system patched on daily basis.

Protecting Your Home Wireless Network

While the security problems associated with wireless networking are serious, there are steps you can take to protect yourself. The following sections describe these steps.

Make Your Wireless Network Invisible:
Wireless access points can announce their presence to wireless enabled computers. This is referred to as “identifier broadcasting.” In certain situations, identifier broadcasting is desirable. For instance, an internet cafe would want its customers to easily find its access point, so it would leave identifier broadcasting enabled.

Rename Your Wireless Network:
Many wireless access point devices come with a default name. This name is referred to as the “service set identifier” (SSIS) or “extended service set identifier” (ESSID). The default names used by various manufacturers are widely known and can be used to gain unauthorized access to your network. When you rename your network, you should choose a name that won’t be easily guessed by others.

Encrypt Your Network Traffic:
Your wireless access point device should allow you to encrypt traffic passing between the device and your computers. By encrypting wireless traffic, you are converting it to a code that can only be understood by computers with the correct key to that code.

Change default Administrator Password:
Your wireless access point device likely shipped with a default password. Default passwords for various manufacturers are widely known and can be used to gain unauthorized access to your network. Be sure to change your administrator password to one that is long, contains non-alphanumeric characters (such as #, $, and &), and does not contain personal information like your birth date or phone numbers etc. If your wireless access point does not have a default password, be sure to create one and use it to protect your device.

Use File Sharing with Caution:
If you don’t need to share directories and files over your network, you should disable file sharing on your computers. You may want to consider creating a dedicated directory for file sharing, and move or copy files to that directory for sharing. In addition, you should password protect anything you share, and use a password that is long, contains non-alphanumeric characters (such as #, $, and &), and does not contain personal information like your birth date or phone numbers etc. Never open an entire hard drive for file sharing.

Keep Your Access Point Software Patched and Up to Date:
From time to time, the manufacturer of your wireless access point will release updates to the device software or patches to repair bugs. Be sure to check the manufacturer’s web site regularly for any updates or patches for your device’s software.

Check Your Internet Provider’s Wireless Security Options:
Your internet service provider may provide information about securing your home wireless network. Check the customer support area of your provider’s web site or contact your provider’s customer support group.

Latest Threats to Home Wireless networks

If you’re planning to move to a wireless connection in your home, take a moment to consider what you’re doing: You’re connecting a device to your DSL or cable modem that broadcasts your internet connection through the air over a radio signal to your computers. If traditional wired connections are prey to security problems, think of the security problems that arise when you open your internet connection to the airwaves. The following sections describe some of the threats to home wireless networks.

Piggybacking:
If you fail to secure your wireless network, anyone with a wireless enabled computer within range of your wireless access point can hop a free ride on the internet over your wireless connection. The typical indoor broadcast range of an access point is 150 to 300 feet. Of course in outdoors, this range may extend as far as 1,000 feet. So, if your neighborhood is closely settled, or if you live in an apartment or condominium, failure to secure your wireless network could potentially open your internet connection to a surprising number of users. Doing so invites a number of problems:

• Service violations: You may exceed the number of connections permitted by your internet service provider. 
• Bandwidth shortages: Users piggybacking on your internet connection might use up your bandwidth and slow your connection. 
• Abuse by malicious users: Users piggybacking on your internet connection might engage in illegal activity that will be traced to you. 
• Monitoring of your activity: Malicious users may be able to monitor your internet activity and steal passwords and other sensitive information. 

Direct attack on your computer: Malicious users may be able to access files on your computer, install spyware and other malicious programs, or take control of your computer.

Wardriving:
Wardriving is a specific kind of piggybacking. The broadcast range of a wireless access point can make internet connections possible outside your home, even as far away as your street. Savvy computer users know this wireless network range, and some have made a hobby out of driving through cities and neighborhoods with a wireless equipped computer sometimes with a powerful antenna searching for unsecured wireless networks. This practice is nicknamed as “wardriving.” Wardrivers often note the location of unsecured wireless networks and publish this information on web sites. Malicious individuals wardrive to find a connection they can use to perpetrate illegal online activity using your connection to mask their identities. They may also directly attack your computer, as noted in the “Piggybacking” section above.

Unauthorized Computer Access:
An unsecured wireless network combined with unsecured file sharing can spell disaster. Under these conditions, a malicious user could access any directories and files you have allowed for sharing.