Spreading virus

There are a few ways to get your computer infected with virus, i.e. penetration through your firewall and installing infected software.

Hackers could penetrate a firewall and drop a virus in your computer. Therefore scanning your computer regular would help to detect known viruses. By the way, hackers could rename a virus, thus antivirus software may fail to detect it. Usually antivirus software scans a virus based on its name.

Another common problem was installing free software or cracked software over the Internet. Hackers could embed their virus in that software. For example, a legitimate filename was printer.dll. However, hackers could append or pack that file with virus file, so that file was larger in size. During installation, the “hacked” file printer.dll would be extracted to smaller legitimate printer.dll plus virus to your computer.

Cracked software means software was hacked and disables its license mechanism. This could be done by a hacker.

Why did we propose “no download” policy to several companies? Even an IT expert cannot tell how many files and its real size in “legitimate or hacked” software.

There are many viruses called worms. Those worms would spread from an infected computer to other computers connected in a network.

The best strategy to defend your computer would be “don’t download and install software that you don’t know” AND don’t keep confidential files in your computer. If you needed software, you should try to download it from its service provider. For example, only downloading and installing free Adobe Reader from Adobe web site instead of an unknown web site. Adobe Reader from other web sites could be a hacked version.

If you don’t have confidential files such as credit card numbers in your computer, hackers would not bother to break in your computer.