In the early days of computers before the Internet, hackers had to communicate through the telephone lines. Since making multiple long-distance phone calls for extended periods of time cost money, hackers soon learned to manipulate the telephone company's computers to make free phone calls or wipe out previously recorded charges on their phone bills.
These early hackers, dubbed phone phreakers, also developed tools to help them control and cause havoc over the telephone lines. While most hackers spend their time creating Internet tools, a few phone phreakers still exist and many hackers still find that phone phreaking tools can help them sneak into a computer through the telephone lines when the usual Internet connections are too heavily protected by firewalls and intrusion detection systems.
Master Credit Card Generator created seemingly valid credit card numbers using the same formula that the credit card companies use. By using a program such as Master Credit Card Generator, hackers could create fictitious credit card numbers to help them set up Internet accounts through online services such as America Online. Once the online service verified that the credit card number wasn't valid, they would shut down the hacker's account, but with the aid of a few dozen more credit card numbers, hackers could simply create new accounts over and over again.
In the early days of the telephone network, the telephone company's switches communicated by emitting specific tones to one another. If you knew which tones to use, you could play those tones into an ordinary telephone and literally reprogram the telephone company's computers. Although these tones no longer work on the newer telephone networks, a program like CyberPhreak shows a typical tone box generator program that phone phreakers have created.
CyberPhreak (see Figure B-12) mimicked the two common telephone color boxes that phone phreakers once used to manipulate the telephone networks: blue boxes and red boxes. A blue box emitted the 2600 Hz tone (which is where the hacker magazine 2600 got its name) while a red box emitted tones into a payphone to trick a pay phone into thinking you inserted a nickel, dime, or quarter.
More of a harassment tool than a hacker tool, Shit Talker (see Figure B-13) lets you use the sound capabilities of your computer to create a computer-generated voice that reads insults to someone on the telephone, which can be perfect for dealing with annoying telemarketers.
An old MS-DOS based war dialer that's still used by hackers today, ToneLoc provides a variety of options for hunting out a modem (see Figure B-14). Despite the growing use of the Internet, many corporations and organizations still provide phone modems for connecting to their network, particularly for sales people who need to use remote access programs like PCAnywhere or Carbon Copy to access a computer through the phone lines.
Once a hacker has found a connected modem to attack, the last line of defense is usually a password, which can often be guessed. As a result, many hackers use wardialers to connect to a network and bypass any firewalls that may be in the way.