I got hold of a bunch of my old articles I had written for Deccan Herald some years ago (2002 – 2005). Here is one of them on desktop security. Most of it might sound obvious now but is still relevant.
Here is the complete article.
Any discussion on network security is never complete without the mention of firewalls. If we were to ask people whether their network is secure, the answer would probably be “Yes! we have firewalls installed on our network”. Having firewalls, those properly configured help secure ones network resources. Firewalls are not the only things that ensure complete security. In recent times, firewalls for home PCs and standalone computers connected to the Internet have been introduced by various antivirus and network security companies. These are called personal firewalls.
The reasons for having a personal firewall on your desktop at home:
- With more individuals at home using high speed Internet connections like Cable or DSL (Digital Subscriber Line); hackers have more time to explore the vulnerabilities in these computers and get unauthorized access.
- Nowadays, computers at home are not restricted for use as in playing games and listening to music but also to shop online. Vital information – like credit card numbers are sent through the internet and it is possible for an attacker to have a Trojan (a program that runs stealthily) installed in the computer and send all the typed keys to his email. So, home computers make a good target for hackers.
- Individuals at home are more susceptible to attacks because they use different chat tools like IRC, messengers like ICQ that are vulnerable. These tools reveal a lot about ones computer network like IP addresses. Also, receiving files through these tools from an unknown person exposes the computer, since a direct connection between the sending and receiving computers is established. Therefore, there is no program which can scan the file before it is received. This is where a firewall helps.
- If a home computer does get attacked, most of the victims will not know how to react to it or to plug the holes in their systems.
What is a Firewall?
The term ‘firewall’ is actually borrowed from the construction industry. It is a wall built of fire-retardant materials, designed to prevent or slowdown the spread of fire from one room to another. A firewall acts as an obstacle that protects against a disaster. In the network world, a firewall performs a similar function by acting as a barrier between the trusted zone (your computer or network) and untrusted zone (another network or the Internet). Firewalls are typically installed at the perimeter of a network. They provide a single point for data to enter and leave the network where security rules are imposed. These security rules typically define what type of data should enter and leave the computer by blocking what is not required.
For example, all you do from your PC is browse a few websites without downloading any programs or files like mp3s. You can just allow HTTP (Hypertext Transfer Control Protocol) data to leave your network. If you try to upload or download files using FTP (File Transfer Protocol), it gets blocked at the firewall. Any incoming connection to your computer can either be blocked or monitored (filtered) using a firewall. With some firewalls, you also get a prompt every time an application tries to connect to the internet or somebody tries to connect to your machine. This prompt will ask for your permission to allow this connection or not. This is very helpful to find out if Stealth programs like Trojans, key loggers or worms are running and sending information out to the attacker.
There are several commercial personal firewalls from companies like Symantec, McAfee etc. Some of them are available for a free download and can be used for a short period of time. Zone Alarm from ZoneLabs (http://www.zonelabs.com) is a freely downloadable firewall, which has no time or feature restrictions. It comes with pre-configured firewall rules and has many more features than some of the other commercial personal firewalls. Configuring the firewall is as easy as using a slider. You can use the slider to change the level of security you prefer.
It can remove or restrict access to all the shares in your PC, hide your IP address and other details from outsiders. In addition, it has other features like alerting when the system blocks an intrusion attempt. ZoneAlarm also displays the IP address of the machine from which the intrusion attempt came from. So, you can track the intruder down and report it to his/her ISP. Furthermore, you can also provide permission to only those programs that should access the Internet.