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vishal sharma 23May2006 11:06

Securing Wi-fi Networks
 
WHAT IS WI-FI?

Wi-Fi is the name given to man’s quest for wireless networking. Even though wireless communications were possible in the past also, thanks to GSM, CDMA, Infrared, Bluetooth etc, the paltry data rates provided by these standards were hardly enough to sustain networks.

Wi-Fi stands for Wireless Fidelity. It ensures mobility and yet retains the data rate which is comparable to wired networks. It is the name given to the set of standards belonging to the 802.11 category instituted by the Institute of Electrical and Electronic Engineers (IEEE). It basically comprises of the following standards:

Standard Frequency Speed

1. 802.11a 5 GHz 54 Mbps

2. 802.11b 2.4 GHz 11 Mbps

3. 802.11g 2.4 GHz 11 Mbps

THE NEED FOR WI-FI SECURITY:

In a wired network the system can be hacked into only through a system attached to a network. Data interception, data alteration and intrusion are possible only when the hacker can access a node attached to the network in some manner.

But Wi-Fi works on wireless technology. This means that any machine with a wireless network adapter can gain entry into a wireless network. Devices that allow scanning of wireless access points are available cheap (compared to the amount of data they can possibly allow access to) in the market. This further simplifies the job of a potential hacker who can use it to track users. All a hacker needs to do is to be in the range of a wireless network. Then he can simply intercept the signal (sniffing), manipulate it and get access into the network (spoofing). For example a business man transferring his money to an account while sitting in a Wi-Fi enabled Mc Donald’s can easily be cyber looted by a hacker sitting in the opposite end of the restaurant if he has a wireless adapter and the tools needed to intercept and modify the signals. The recently occurred Lowe’s case in North Carolina is proof enough that Wi-Fi is certainly not so safe for transferring sensitive data like credit card numbers, company plans or the personal health records of a company’s employees. This is reason enough for users to secure their networks in all possible ways.

THE METHODS FOR SECURING WI-FI:

SSID: Service Set Identifier is a 32 character unique identifier attached to the header of the packet transferred over the wireless connection. It distinguishes one network from another. All Access Points belonging to the same network have a common SSID. It is like a school scenario where the students of a particular class are identified by their class name.
The SSID is also called the Network Name.
When a new Access Point is installed the default SSID value should be changed and should be assigned a network key. This serves as a basic means of security and privacy.

WEP: Wired Equivalent Protocol was proposed by the IEEE to bring the level of security enjoyed by wired networks to wireless networks. WEP uses secret encrypted keys to alter the data bits passing in a wireless network. This ensures (or at least used to) that even if the data is sniffed, without the key, it will be rendered useless. This key is made available only to the source and destination parties. It is more like a symmetric cryptography scheme.
The encryption can be 64 bit, 128 bit or 256 bit. Till recently 64 bit was safe enough but with rumours that a crack for this key has been found, it is advisable to use 128 bit or 256 bit encryption. Another way to keep data secure while using WEP is to frequently change the key. A downfall to this is that it is susceptible to man in the middle attacks (the key can be stolen while it is being exchanged).

ACL: Access Control List is a table of the MAC addresses of all access points in the network. The MAC (Media Access Control) address is a unique address assigned to each wireless device. The ACL ensures that only those MAC addresses which are present in the list are allowed to enter the network. The downfall to this is that the MAC addresses can be stolen and spoofed.

IEEE 802.1x: This is basically a method of security based on the principle of network restriction through user restriction.
This standard recommends the use of a Remote Authentication Dial In User Service (RADIUS) server. This is used along with two data communication protocols viz. Extensible Authentication Protocol (EAP) and Transport Layer Security (TLS).
The RADIUS server requires the user to login with a user name and password and also answer an encryption key question. The request is then constructed and wrapped in a specific manner based on the EAP/TLS standards. TLS prevents sniffing and tampering of the communication channel and also prevents message forgery. This is brought about by the use of a trust relationship between the source and destination by means of a certificate of validity. This is provided by a trusted third party certifying authority. An extension to this is called the Tunneled Transport Layer Security (TTLS)
FIPS 140: Federal Information Protection Standard 1.40 is a higher level security. It provides data encryption of different types like Advanced Encryption Standard (AES) or Triple Data Encryption Standard (3DES). Since the level of encryption provided by these standards is almost impossible to crack, as of now this is the best method of security available.

SUMMARY:

Securing wireless networks can seem to be a complicated process. Many times users are just too ignorant about the aspect of security. They think “Why would anyone hack me? That is really a silly question because a hacker doesn’t need motivation to hack; all he needs is a chance. Some users even if concerned about security find implementing it confusing. At such times it is advised to take the help of manuals on the same or better yet get professional help. It is a small price to pay for keeping your data and privacy safe.

And last but not the least; ensure to follow the three tier step of networking:
1. Plan 2. Implement 3. Test
This basically means that plan before setting up your network. Be clear with your network. Understand why you want to network. Then get a tailored security package according to your network. Use different methods together to attain the desired level of security. Plan a security policy and make sure to enforce it.
Implement your network along with the security package and security policy. Make sure all users adhere to the policy.
Test your network. Once you finish setting up your network check for unknown access points. Try to sniff your own signals. See if your network can be compromised in any way. Watch out for suspicious activity in the range of your network. If you feel that your network is still weak in some manner then plan again, improve the measures, implement the new packages and again test it. This should be a continued cycle.

arvindsony 2Dec2008 22:15

Re: Securing Wi-fi Networks
 
thankx


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