A computer network is a group of interconnected computers. A network is nothing but a collection of computers and related devices connected through wired or wireless devices or other media. This network allows computers to exchange information with each other and share resources. It is consists of millions of private and public, academic, business, and government networks of local to the global scope.
The Internet is the network of networks. It is a network of extremely fast network components and computers providing the backbone of such service. It is a global network of interconnected computers, allowing users or hosts alike to share information side by side with multiple channels. It offers a facility to connect to various sources of information from a vast array of accessible servers and computers by exchanging information from them to the computer. In the same way, this connection allows the host computer to send information to servers on the network.
Computer users typically handle sent and received information with web browsers or other software with users’ interfaces with internet or computer networks, which include specialized programs like electronic mail, online chat, file transfer, file sharing, etc. This movement of information on the Internet is achieved with the help of a system of interconnected computer networks that share data by a method called packet switching using the standardized Internet Protocol Suite (TCP/IP).
This vast array of available resources also poses security risks as most of the data personal or confidential are maintained online using so-called secured computers. This vast array of information may include your identity-related information to personal details to tax details, almost nearly everything. These days this information be it be for business or personal use is in great demand, along with it comes the need for hijacking this information for fun or specific use. This is the reason for the last decade or so there have been so many attacks against networks around the world. This is where network security comes in.
Network security consists of the requirements made in a fundamental computer network infrastructure, policies adopted by the network administrator to defend the network, and the network-accessible resources from unauthorized access. It includes regular and uninterrupted monitoring and testing of its efficiency or its inefficiency (or its inability to sustain attack).
In 1983, the U.S. Department of defense made the Trusted Computing System Evaluation Criteria (TCSEC), known as the orange book defined computer systems according to the following scale
D Minimal protection or unrated
C1 Discretionary security protection
C2 Controlled access protection
B1 Labeled security protection
B2 Structured protection
B3 Security domains
A1 Verified design
The orange book defined functional requirements as well as assurance requirements, for each requirement. However, these rules never defined criteria for network security (Chakraborty, pp. 59-63).
Network security starts from authenticating any user, usually with a username and a password. Other than physically giving a username and password there are other methods used in conjunction like using a security token or ‘dongle’, an ATM card, mobile phone, etc. Other devices like a fingerprint scanner or retinal scanner, radio-operated devices are also used for authentication. After authentication, there are administrative policies that govern the access or the level of access to the resources of the network the authenticated user has over the network.
In some cases, external devices like software or hardware firewalls are also employed. Though deemed effective to prevent unauthorized access, this security element or service often fails to check potentially harmful content such as computer worms or Trojans being broadcasted over the network. For this very purpose, an intrusion prevention system (IPS) helps in ensuring detection and inhibition or alienation of such malware or destructive software (Ammari, pp. 946-8).
Even this is just not enough for securing the network from determined users. Some of the network threats are IP spoofing, IP Session hijacking, denial of service (DOS), unauthorized access, executing commands illicitly, confidentiality Breaches, destructive behavior, data diddling, data destruction, etc. In addition, a. there are attacks like hijacking a webcam, pinpointing a person’s location with a cell phone, reading a person’s email, and following someone’s movements.
IP Spoofing is where one host claims to have the IP address of another. Here the hacker creates IP packets with a forged or spoofed source IP address with the sole intent of hiding the identity of the sender of packets or using impersonating another computing system by using the fake IP address of the intended sender of packets. Internet is commonly accessed by the use of browsers, in browsers cookies are used to store session information like that of the authentication and session details.
This session cookie of the user’s session is being taken control over. If the user was in the middle of an email or any monetary transaction, the attacker is going through the email and learns the user’s detail or knows of the transaction details taking place. The attacked user finds session dropped when he might log in again, while the attacker is still logged in doing mollified jobs.
Webcam is one of the widely used devices on the internet. This device is used to transmit images and sounds of the user working on the internet. This device can be taken control over by Trojans like malware or some software can be remotely installed on the user’s computer and time-sliced images can be sent to a remote computer, to watch the user movements.
This was demonstrated by researcher Grossman, a method known as clickjacking, and any computer with a microphone and/or a web camera attached can be invisibly coaxed in to being a remote surveillance device, exploiting the Flash component usually used for see videos on YouTube. Details can be seen on the website.
Now a day’s even personal identity to pinpointing a person’s location with a cell phone is coming within the ambit of hackers. There are services available offered by companies for this very purpose. Hackers can very well use or hack these services to find locations on the internet. There are many cell phones that use services like blackberry and as well as GPS devices. It would not be hard to imagine how this exploited using a Trojans or worms on the devices can read the GPS device or the cell phone info of the nearest tower location and send the into to net to the hare cker.
Emails one of the oapplications used application on the internet, typically used via software like email clients or hosted emails. These programs are often forced open by hackers by using a user’s username and password. By open the email of the user, the hacker can now read the emails and modify it. Keylogger, a keystroke logger, or any kind of system monitor, is such device or program that is often used for this purpose. Keylogger as the name suggest reads keystrokes made by user on the computer and the username and passwords. For this purpose, even screenshots are taken as well as user’s webcam is also taken control. There are also password crackers in use like brute-force, which essentially is password-guessing software, from its database of passwords.
Another kind of attack seen in recent times is tracking the user, making the profile of the user and selling it to companies, which request it. Also even some personal attacks are also done in recent times. When any user uses a browser, browses a website, each or most website leave a trail on the hard disk. Most website browsed makes user profiles on the site, which the user browses. This is done with help of cookie.
In addition, every site browsed by the user leaves information on the about the site visited, known as browser history. Other than, this browsers cache some of the most visited sites so the display time is less than first visit. This information can be accessed by any malware program and transmitted over the net giving the user’s internet behavior and habits. This when followed in minute details will give the user trails, which can be exploited by malicious person (Farmer, pp. 227-31).
Network is a difficult topic. This basic idea of network security is based on the requirements of the organization. Devices like hardware firewall routers can be implemented, even security experts include ethical hackers can be employed based on security requirement. With one word of caution ‘no security is good enough’, because hackers will always reinvent themselves, so should the network security experts.
- Ammari, Habib M. “A survey of current architectures for connecting wireless”. International Journal of Communication Systems, 20:8 (2007), 943-968.
- Chakraborty, Goutam, Vishal Lala, David Warren. “An empirical investigation of antecedents of B2B Websites’ effectiveness” Journal of Interactive Marketing; 16:4, (2002), 51-72
- Farmer, Dan and Wietse Venema. Forensic Discovery; New York: Addison-Wesley, 2004.