Glossary of Security Terms

Adware	Adware (which works much like spyware) installs itself on a computer and then creates pop-up windows attempting to sell items to the computer user.
Antivirus Program	Anti-virus programs use virus definitions - descriptions of what computer viruses look like or how they act - to identify viruses. The program will then quarantine or delete the virus to prevent it from damaging the computer. Anti-virus programs need to have their definitions updated regularly (daily is recommended) and to be run constantly to maintain protection against viruses.
Browser Hijacker	Browser Hijackers are either virus or spyware that sets your home page to a site and won't let you change it, or keeps displaying advertisements in your browser. Some Hijackers will load your browser without you asking it to start and begin showing you advertisements.
Cookies	Most cookies are benign or even beneficial and do not pose a security risk. Tracking cookies make you a better target for online advertisers, but cookies pose no danger to your computer as they can't be used to launch a virus or cause other problems on your computer.
Denial of Service	Denial of Service or DOS attacks are usually directed at specific commercial web sites. Often Trojan Horses which have been placed in computers around the world mount the attack, directing millions of queries at the web servers being attacked. The attacks have the immediate goal of preventing others from accessing the servers. At times Denial of Service attacks will cause web servers to crash, disabling web sites.
Firewall	A firewall, which can be either software or hardware, is designed to control or completely block access to a computer or computer network from the Internet.
Identity Theft	While lack of computer security can allow identity theft to take place, identity theft does not require use of a computer. It involves a criminal acquiring enough information about a person that they are able to act as that person by charging to their credit cards, making withdrawals from their bank accounts and opening up new accounts in the victim's name.
Key Logger	A software program or a hardware device which captures keystrokes on the computer for later retrieval. They can be used as a way to track computer use, or to steal passwords and other personal information. They can work like a Trojan Horse, capturing data and then sending it back to the person who wrote the program.
Malware	A new term which includes all computer programs designed to do harm - viruses, Trojan horses, worms, adware, spyware, etc.
Nigerian E-Mail	Nigerian e-mails ask for help retrieving millions of dollars and offering a substantial commission for your efforts. If you take the bait, they then start asking you for money to pay for "fees" or "travel expenses" and continue to promise you handsome rewards for little effort.
Phishing	Phishing is sending out e-mail messages purporting to be from some official source such as a bank, auction web site, etc., in an effort to get personal information from the recipient by tricking them into thinking they need to respond to the message.
Router	A hardware device which may include a firewall.
Spam	Also known as unwanted commercial e-mail. The name Spam comes from the Monty Python skit, "Spam, Spam, Spam, Spam".
Spyware	Software which is installed on a user's computer but is designed to serve the needs of its creator. Spyware most often tracks a user's activities on the Internet and sends reports to its home server. Many spyware programs are poorly written and hurt computer performance.
Trojan Horse	A Trojan Horse is a piece of software code which doesn't intend to damage its host computer, but has another goal. Some malicious code writers will try to place Trojan Horses into as many computers as possible that will then use their own Internet connections to execute a denial of service attack against a web server by flooding it with file requests at a predetermined time. Often a Trojan Horse's goal is to spread a virus to other computers by setting itself up as a mail server on the computer and sending out copies of itself to e-mail addresses it finds on the computer or to randomly generated e-mail addresses in the hope that the virus will be able to infect other computers.
Virus	A virus is a piece of software code, sometimes quite small. More than 60,000 viruses have been detected since virus writers started doing their damage 20 years ago, although relatively few of them are being passed around at any time. Viruses change files on your computer, either by attaching themselves to existing files or by replacing files with their own copies. All viruses have the ability to replicate and pass to other computers.
Worms	Worms are software code primarily designed to replicate itself. Some worms will keep replicating themselves until the entire hard drive is full. Others seek to spread themselves to other computers. While worms can make it difficult to use a computer by sapping all the computing power and disk space, they generally don't damage the computer itself.

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