Internet Security: How People Can Take Over Your PC - dummies

Internet Security: How People Can Take Over Your PC

By John R. Levine, Margaret Levine Young

You can download and install software directly over the Internet, which is a useful feature. However, other people can also install programs on your computer without your permission, and this isn’t good for you or your computer.

Viruses arrive by email

Computer viruses can spread using any mechanism that computers use to talk to each other, such as networks, data CDs, and DVDs.

What viruses do

When a virus lands on your computer, it has to manage somehow to get executed. Getting executed in computer jargon means being brought to life; a virus is a program, and programs have to be run in order to do their nefarious work. After a virus is running, it does two things:

  1. Looks around and tries to find your address book, which it uses to courteously send copies of itself to all your friends and acquaintances, often wrapped up in authentic-sounding messages.

  2. Executes its payload, which is the reason that virus writers go to all that trouble and assume the risk.

The payload is the illegal activity that the virus is running from your machine. A payload can record your every keystroke (including your passwords). It can launch an attack at specific or random targets over the Internet.

What you can do about viruses

Consider installing a virus checker. After you install it, be sure to update it regularly so that you’re always protected against the latest viruses. You can subscribe to receive updates automatically.

Worms come right over the Net

A worm simply jumps directly from one computer to another over the Net, entering your computer by way of security flaws in its network software. Unfortunately, the most popular type of network software on the Net, the kind in Microsoft Windows, is riddled with security holes.

If you rigorously apply all security updates from Microsoft, they fix most of the known security flaws, but it takes a lot longer than a minute to apply them all. Therefore, anyone using a broadband connection to use a hardware firewall, a box that sits between the Net and your computer and keeps the worms out. If you have a broadband connection, you probably should use an inexpensive router to hook up your computers, anyway, and all these devices include a firewall as a standard feature.

Spyware arrives via websites

Spyware is downloaded by your browser. Generally, you need to click something on a web page to download and install spyware, but many people have been easily misled into installing spyware that purports to be a graphics viewer or another type of program they think they might want.

Know what spyware does

Sometimes, spyware gathers information about you and sends it off to another site without your knowledge or consent. A common use for spyware is finding out which sites you’re visiting so that advertisers can display pop-up ads that are targeted to your interests.

Targeted advertising isn’t inherently evil. The Google AdSense program, for example, places ads on participating web pages based on the contents of those pages.

Don’t voluntarily install spyware

Most free toolbars, screen savers, news tickers, and other utilities are spyware in disguise. Download programs only from reputable websites.

This advice is particularly important on your mobile device. Some free apps are free because the programmer wrote them for fun, or they provide access to a commercial site, or they hope they can get you to upgrade to a more capable paid version. But some are free because they show ads and report back to headquarters.

Protect your computer from spyware

To block spyware, be careful about the screen elements you click. Install a spyware checking program that can scan your system periodically, such as the free Microsoft Windows Defender.

Spyware can attack Macs and even phones

The Macintosh operating system is by design more secure than Windows, so few viruses and little spyware attack it. But a Mac user is just as likely as a PC user to be fooled into clicking a link to a free porn site that downloads spyware to your computer along with that sexy video. Even smartphones can be infected with spyware, and although most spyware targets Windows, it also targets other kinds of computers and phones, so think before you click on any of these devices.

Pop-up browser windows pop up all over the place

One of the worst innovations in recent decades is the pop-up window that appears on your screen unbidden when you visit certain websites.

Several mechanisms can make pop-ups appear on your computer:

  • A website can open a new browser window. Sometimes this new window displays an ad or other annoying information. But sometimes the new window has useful information — some websites use pop-up windows as a sort of Help system for using the site.

  • Spyware or other programs can display pop-up windows.

Luckily, web browsers now can prevent most websites from opening unwanted new browser windows.

What’s the secret word, Harry?

Security experts are nearly unanimous in telling internet users how to protect passwords:

  • Pick complex passwords that are long enough that no one can guess them.

    Never use as a password a word that occurs in the dictionary. Consider sticking a number or two into your password.

  • Never use the same password for different accounts.

  • Memorize your passwords and never write them down.

  • Change your passwords frequently.

  • Find out how hard a hacker would have to work to guess your password. Microsoft has a site that helps you with this.

When making up a password, stick numbers and punctuation into words or glue two words together with some numbers, or spell things backward. Use both capital and lowercase letters, too.

If you have a lot of passwords and no way to remember them, consider using a password manager, which is designed to store your passwords in a safe place. You can use KeePass, a freeware, open source program for PCs and Macs.