When strangers send an email or invite you to visit a website, DELETE THE EMAIL IMMEDIATELY. DO NOT OPEN THE EMAIL OR VISIT THE WEBSITE. Your computer could be infected with downloaders which allow others access into your network system. One downloader in the system is enough to enable the trespasser to access and effect changes in the network. The downloader could modify data in a compromised bank network, for example, by adding a few zeroes to their accounts.

If up-to-date anti-virus had been installed on the computer, the downloader would have been detected and stopped in its tracks. However, the system is vulnerable without the protection of a security appliance or suite. The initial downloader is usually equipped with a random character generator so that it is not easily detected for new downloads, are used and they are often encrypted. A firewall would not have stopped this as they are set to allow users access to websites rather than screen them. But it can be prevented with the ability to scan packets coming through Port 80, the browser (http) port.

A targeted attack can be small scale or large and the consequences can be equally unpredictable. The virus Blaster was a targeted broad-based attack on the Microsoft.com update centre that, however, led to no financial gain. Others like SoBig dropped in as a worm that terminated itself after a few days, thus, less easily detected or eliminated.

In order to protect yourself from these targeted attacks, install up-to-date security software that blocks malware at the Internet gateway. But technology is ever changing. So don’t open that email or click on that link!