As the cost of hacking attacks continues to rise, businesses have been forced to increase spending on network security.
However, hackers have also developed new skills that allow them to break into more complex systems.
Hacking typically involves compromising the security of networks, breaking the security of application software, or creating malicious programs such as viruses.
The most popular forms of network hacking are
denial of service (DoS) attacks and
mail bombs.
DoS attacks are designed to swamp a computer network, causing it to crash. Mail bombs act in a similar fashion, but attack the network's mail servers.
When eBay was attacked in February 2000, its Web server was bombarded with fake requests for Web pages, which overloaded the site and caused it to crash.
Network hackers
also try to break into secure areas to find sensitive data. Once a network is hacked, files can be
modified,
stolen, or
erased.
A group of teens in Wichita, Kansas, for example, hacked into AOL and stole credit card numbers that they then used to buy video games.
Application hackers
break security on application software—software including word processing and graphics programs—in order to get it for free.
One way they gain access to software that requires a serial number for installation is by setting up a serial number generator that will try millions of different combinations until a match is found.
Application hackers also sometimes attack the program itself in an attempt to remove certain security features.
Hackers that create
viruses,
logic bombs,
worms, and
Trojan horses are involved in perhaps the most malicious hacking activities.
A virus is a program that has the potential to attack and corrupt computer files by attaching itself to a file to replicate itself.
It can also cause a computer to crash by utilizing all of the computer's resources.
For example, e-mail systems were inundated with the "ILOVEYOU" and the "Love Bug" viruses in May of 2000, and the damage to individuals, businesses, and institutions was estimated at roughly $10 billion.
Similar to viruses, logic bombs are designed to attack when triggered by a certain event like a change in date.
Worms attack networks in order to replicate and spread. In July of 2001, a worm entitled "Code Red" began attacking Microsoft Internet Information Server (IIS) systems.
The worm infected servers running Windows NT 4, Windows 2000, Windows XP, and IIS 4.0 and defaced Web sites, leaving the phrase "Welcome to
Worm.com Hacked by Chinese!"
Finally, a Trojan horse is a program that appears to do one thing, but really does something else.
While a computer system might recognize a Trojan horse as a safe program, upon execution, it can release a virus, worm, or logic bomb.