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Home Network Vulnerabilities: Spam, Cookies, Pop-Ups, Spyware, and Scams

Chapter Description

In addition to viruses and worms, there are some other annoying programs and files out there that you need to protect your home network from. This chapter focuses on spam, cookies, spyware, and scams—what they are, how they work, and how to get rid of or at least control them.

From the Book

Home Networking Simplified

Home Networking Simplified



Cookies are small text files that web pages place on your computer when you visit a web page. The text file contains information that helps web pages track users and allows site preferences so that when you re-enter a page, it's unique to your custom settings or has "one-click" purchase options.

How Cookies Work

When you visit a website that tracks user data in this way, the site "drops a cookie" and creates a text file on your machine if it is your first visit, or updates a file that it left on your machine from a previous visit. The website does not change anything on your computer other than the file and, in all but the rarest of cases, the cookie does not contain any private information such as credit card numbers or home addresses and phone number. Most often, the cookie contains only the name of the web page and a unique identifier that the web page uses to pull information from a secure database where the private information about you is kept. This helps prevent problems associated with different people sharing the same machine, or a single user who switches between machines. It also allows web pages to keep track of users even when they have deleted all their cookie files.


Cookies are text files that websites place on your computer to help them keep track of visitors and customized settings. Most of the time, cookies are harmless, but you should set your privacy settings to at least "Medium High" to avoid cookies from sites that share your information with others.

  1. The first time you visit a website, web it has no record of you
  2. To keep an accurate count of how many unique visitors come to the site, the web page places a "cookie" on your computers hard drive.
  3. If the website allows personalized views or purchase settings, the cookie helps the site load your settings so you do not have to enter it every time you visit.
  4. Your personal information is not sent within the cookie's file, only a number points to a table in a secure database on the site.

    Cookies can be used as a form of spyware when thay are shared and aggregated among different sites

Bad Cookies

Not all cookies are bad things. For example, http://www.weather.com may place a cookie on your computer to store your ZIP code so that each time you return to its website, it can immediately bring up the local weather for your location.

However, one of the main issues with cookies is that marketing companies often use information about what you buy and where you click on a web page to better target you for advertising and spam. Some cookies are tracked across multiple sites by third-party companies. This is considered a privacy or security violation by many users. To protect your personal information, you can set your Internet browser to one of various privacy settings ranging from accept all cookies to block all cookies. Both these options are a bit impractical because accepting all will greatly increase security risks and blocking all will make it very difficult to browse many private and commercial websites (the pages will fail to load).

On Internet Explorer, we recommend a setting of Medium High as Figure 16-1shows. (The screen is found by selecting the Privacy tab on the Internet Options dialog box, which is found under the Tools drop-down menu on the top of the browser.)

Figure 1

Figure 16-1 Setting Your Privacy to Medium High in Internet Explorer

If you are worried about the cookies you have previously accepted, you can delete all cookies by selecting the Delete Cookies button on the General screen of the window shown in Figure 16-1. If you had your privacy setting set to anything below Medium High, you should probably do this when you reset your settings.