The very nature of the Internet makes it vulnerable to attack. It was designed to allow for the freest possible exchange of information, data, and filesand it has succeeded admirably, far beyond its designers' wildest expectations. However, that freedom carries a price: Hackers and virus writers try to attack the Internet and computers connected to the Internet; those who want to invade others' privacy attempt to crack databases of sensitive information or snoop on information as it travels across Internet routes; and distasteful and pornographic sites have sprung up on the Web and on Usenet newsgroups.
This section of the book looks at a variety of security-related issues. You'll see how hackers target websites, invade your PC, and create vast armies of "zombie" networks that can be used to attack computers and sites whenever the hacker tells them to. You'll find out details about the dangers inherent in using wireless technologies, and see how viruses work. You'll also examine how websites can invade your privacy every time you visit.
There's a lot more in this section as well. Various tools have been developed to make transactions on the Net more secure and to help companies protect their sensitive data. You'll examine the thorny issue of pornography versus free speech and see how software can block children from visiting obscene sites or getting obscene materials. You'll also learn about some of the more controversial technologies on the Internet, such as cookies, which enable web servers to track your movements through their sites. This section also takes an inside look at an even more controversial technology, the National Security Agency's Echelon program, which allows it to wiretap, read email, and find out about people's Web surfing habits all over the world. You'll also look at how viruses work and how hackers attack Internet service providers (ISPs).
Chapter 44, "How Firewalls Work," looks at firewalls. Many companies whose networks are connected to the Internet have a great deal of sensitive information on their networks and want to ensure that their data and computers are safe from attack. The answer is to use firewallssystems that allow people from inside a company to use the Internet but also stop people on the Internet from getting at the company's computers. This chapter also discusses personal firewallssoftware people can use at home to ensure that hackers can't invade their own computers.
Chapter 45, "How Hackers Can Cripple the Internet and Attack Your PC," looks at attacks launched by hackers that can cripple ISPs and attack your computer as well. In a Denial of Service (DOS) attack, also called a smurf attack, or smurfing, a hacker targets an ISP and floods it with so much "garbage" traffic that none of the ISP's customers can use the service. Smurfing is one of the most common types of hacking attacks on the Internet. This chapter also examines the various ways hackers can attack your PC.
The chapter also gives you the rundown on zombie networks, which can be used by hackers to attack sites and computers at will. It also shows how viruses can invade your PC via email, and how hackers exploit browsers to invade your PC.
Chapter 46, "The Dangers of Wireless Networking," delves into the newest dangers to hit the Internet. Millions of people connect to the Internet wirelessly every day, using home wireless networks, wireless networks at work, public hot spots in cafes and similar locations, and via their cell phones. Every time they connect, they court danger, as this chapter shows you. The chapter details how hackers go "war driving" to find wireless networks to invade, and shows how they use a nefarious technique called an "Evil Twin" hack to fool you into giving up your personal information. The chapter also shows how you can protect yourself against wireless hacks and how B-list celebrity Paris Hilton had her cell phone hacked.
Chapter 47, "How Viruses Work," looks at viruses and how they are detected. Any program you download from the Internet has the potential for being infected with a virus and could infect your computer. You'll see just how these nasty data-killers work and look at antivirus tools that can detect and kill them. This chapter also examines how a special type of virus called a worm works. Worms are becoming increasingly common on the Internet, so you'll look at one of the most infamous wormsMelissaand how it affected the Internet.
Chapter 48, "How Internet Sites Can Invade Your Privacy," explores controversial technologies that enable websites to track what you do when you're online. It covers cookies, web tracking, and web bugs, as well as a technology that can help preserve people's privacyInternet passports. Some people worry that cookies and web tracking can invade their privacy. Others disagree, saying that cookies and web tracking can help customize the Web to users' interests. Cookies are bits of data put on a hard disk when someone visits certain websites. That data can be used for many purposes. One common use is to make it easier for people to use websites that require a username and password by storing that information and then automatically sending the information whenever it's requested. Passports enable people to decide what type of information about them can be tracked by websites. Web tracking enables those who run websites to see how people use their sites. Web bugs are another technique for tracking people's Internet use.
Chapter 49, "The Dangers of Spyware and Phishing," looks at two extremely common online dangers. Spyware gets onto your PC in a variety of ways, including piggybacking a ride on free programs, being installed without your knowledge from a website, pop-up ad, or via what are called drive-by downloads. There's a lot of different kinds of spyware that does a wide variety of damage, such as reporting on your surfing habits, stealing your passwords, and reporting every keystroke you make to a hacker.
The chapter also covers phishing attacks, which fool you into giving personal information such as your passwords to banking or financial sites. Both spyware and phishing attacks are done for financial reasons rather than malicious ones, and so the chapter follows the money trail to show you who's making money from the attacks.
Chapter 50, "Cryptography, Privacy, and Digital Certificates," examines cryptosystems and digital certificates. An enormous amount of information is sent across the Internet every dayeverything from personal email to corporate data to credit card information and other highly sensitive material. All that information is vulnerable to hackers and snoopers. Because the information is sent in packets along public routers, the possibility exists that someone could intercept and decipher it. As a way to ensure that the sensitive material can't be looked at, sophisticated cryptosystems have been developed so that only the sender and receiver know what's in the packets.
The chapter also looks at digital certificates. On the Internet, no face-to-face communication takes place, so knowing whether people really are who they say they are can be difficult. Digital certificates are used to absolutely identify someone. If someone sends you an email, for example, a digital certificate will let you know that the person is who he says he is.
Chapter 51, "How Government and Workplace Surveillance Work," details an extremely controversial program that enables the federal government to read people's email and follow their Internet activity without people knowing about it. It also explains how your place of business can track all your Internet use.
Finally, Chapter 52, "Parental Controls on the Internet," takes a detailed look at the issues of pornography and free speech on the Internet. Explicit sexual material is posted on the Internet, and some people would like to fine and jail people and organizations that allow such material to be posted. Passing those types of laws raises a host of constitutional issues about free speech. As a way to solve the problem, companies create and sell software for parents that enables them to block their children from seeing obscene and violent material on the Internet. In this chapter, you'll see how one of the most popular pieces of parental control software works.