Computer Hacking and Security

With the rapid growth of the worldwide Internet user base, online transactions are believed to reach well over a trillion dollars in the next three years. With stakes this high, it makes sense for all parties involved to secure the Internet. Haphazard handling of financial and personal information can lead to the Internet being constantly associated with fraud and privacy abuses instead of being a viable commerce medium. The goal for higher security starts with the individual user.

The term "hacker" has been around for a while. It originally referred to a person not well versed with a computer trying different things to accomplish a task. To hack was to figure out something through sheer trial and error or logical deduction. Today, a hacker described as a person who breaks into computers for various reasons. Crackers and script-kiddies are two other more commonly used terms describing those involved in the break in or disruption of an online service.

Security problems can occur in any networked environment. Many of the problems are related to the exploitation of the original design of the TCP/IP suite of internetworking protocols, but the majority are due to configuration or operator errors. Hackers are not just looking for websites or government computers to hack - utility grids, emergency information systems, controls for dams and locks, financial information, inter-banking information, military communications and much more sensitive information travels on the Internet and other communication networks.

In broad terms, security threats can be classified as active and passive.


Active attacks involve the modification of transmitted data and attempts to gain unauthorized access to systems. Data communication is based on a set of handshakes to ensure the smooth and reliable flow of information. A hacker that is between a client and a server and is able to spoof (illegally duplicate) the IP address and sequence numbers, can attack either machine in several ways. The hacker can disable one of the machines and take the identity of the other, or the hacker can mimic either machine and carry on conversations impersonating the other.

A hacker could also attach additional information to a client request and strip the corresponding additional response from the packet before forwarding the remaining response to the client's original request. All this while having access to information that is assumed to be going back and forth between two 'trusted' systems. Computer viruses and trojans are also examples of active attacks. They can disable machines or in the case of trojans allow malicious hackers access to senstive information by creating a back door.


Passive attacks have to do with evesdropping and monitoring transmissions. All electronic transmissions (email, WWW, telenet, etc) can theoretically be monitored. Since most computers (and the whole Internet) is part of network(s), spying on data transmissions is a major concern. One of the earliest and most sophisticated passive evesdropping example comes to us from the Cold War. The US Navy was able to 'tap' into Soviet undersea fiber optic lines by using special submaries and for years had complete knowledge of that set of communications. On the Internet, protocols like HTTP, FTP and telnet are non-encrypted modes of communications that can easily be compromised. Therefore, encrypted versions (HTTPS, SSH, etc) should be used when transmitting sensitve information.

Refer to the resources section for other interesting links and sources, consider a personal firewall router and check these personal firewall reviews.