Hacker

It is commonly used to refer to any individual who uses their knowledge of networks and computer systems to gain unauthorized access to computer systems. While often used interchangeably, the term hacker typically applies to those who break in out of curiosity or for the challenge it rather than those who actually intend to steal or damage data. Hacker purists claim that true hacking is benign and that the term is misused.

A hacker is a person who is intensely interested in how complex systems, in particular computer systems, work. A cracker extends this interest to unauthorized entry and modification of these systems. The term hacker has also been used synonymously with cracker, much to the dismay of hackers who is sometimes called on to detect, repair, and prevent future damage by crackers.

Phrack is an electronic magazine in publication since 1985 and dedicated to providing information on operating systems, networking technologies, telephony, and news of the international computer underground. Varied topics such as lock picking and construction of acetyline bombs have also been covered in their philes. The uebercracker is a cracker of superior skill, and is very hard to keep out of your systems. Phone phreaks have a fascination with telephone systems. There is no special meaning to the word spy in computer security, but you can be an international arms courier.

IP Session Hijacking

IP Session Hijacking is a relatively sophisticated attack that was first described by Steve Bellovin. It is an attack whereby a user's session is taken over, being in the control of the attacker. If the user was in the middle of email, the attacker is looking at the email, and then can execute any commands he wishes as the attacked user. In these cases the attacked user simply sees his session dropped, and may simply login again, perhaps not even noticing that the attacker is still logged in and doing things.

Mobile Code

Mobile code is ActiveX, Java, and JavaScript. A wicked web developer may attach a script to something sent to a web site, such as a URL, an element in a form, or a database inquiry. Later, when the web site responds to you, the malicious script is transferred to your browser.

The most significant impact of this vulnerability can be avoided by disabling all scripting languages. Turning off these options will keep you from being vulnerable to malicious scripts. But, some times, it will limit the interaction you can have with some web sites. Many legitimate sites use scripts running within the browser to add useful features. Disabling scripting may degrade the functionality of these sites.

Packet sniffing

The program "packet sniffer" captures data from information packets as they travel over the network. These include user names, passwords, and proprietary information. That travel over the network in clear text. With perhaps hundreds or thousands of passwords captured by the packet sniffer, intruders can launch widespread attacks on systems. Installing a packet sniffer does not necessarily require administrator-level access.

Relative to DSL and traditional dial-up users, cable modem users have a higher risk of exposure to packet sniffers since entire neighborhoods of cable modem users are effectively part of the same LAN. A packet sniffer installed on any cable modem uses computer in a neighborhood may be able to capture data transmitted by any other cable modem in the same neighborhood.