The way the communication takes place between the computers in a network is being rapidly affected by the wireless networking technology. At some point where the wireless network technology offers convenience in making connections between the networks via mobile computing devices, it has also introduced a number of security issues that one may not find in the wired network technology.
We have relied up on a number of security measures for securing out networks. These security measures have become obsolete with the introduction of the wireless networking technologies.
Wireless local area networks (WLANs) have proved to be very useful but the encryption and the authentication methods defined for it have some flaws. This has led to some serious issues with the security. The flaws in these standards can be overcomed using the dynamic key distribution and centralized authorization in WLAN, applying the recommendations in the security checklist and deploying them in virtual private networks (VPNs).
The IEEE created a group of specifications called the 802.11 standard for the WLANs. It was first adopted in the year of 1997. This standard defines the physical and the MAC (media access control) layers for the WLANs.
Wireless Equivalent Privacy – WEP
– This is actually an algorithm designed for providing protection to the wireless communications form threats of accidental modification and eavesdropping.
– A secondary function of this algorithm is prevention of the unauthorized accesses to the network.
– It works on the basis of a secret key that is known only by the access point and wireless station.
– This key is used for the encryption of the packets before their transmission.
– It also carries out an integrity check for ensuring that no modification has been made to the packets.
– The above mentioned standard does not say anything about the establishment of this key.
Authentication and Association
– It is necessary for the access points and the wireless clients to establish an association before they start communicating with each other.
– Once this association has been established, exchange of information can take place between the two.
– The client associates with the point in case of the infrastructure mode.
– This association process comprises of the following 3 states:
- Unauthenticated and un-associated
- Authenticated and un-associated
- Authenticated and associated
– Authentication management frames are the messages exchanged by the two parties during the period of transition between the states.
Open System Authentication
– This is the default authentication protocol for the WLAN standard.
– Its purpose is to authenticate the one requesting for authentication.
– In a way it offers the so called ‘NULL authentication process’.
– The messages used here consist of clear text when the WEP is in enabled state.
Shared Key Authentication
– This mechanism makes use of a standard challenge for providing the authentication.
– When a client requests for authentication, it gets a challenge text in authentication request management frame.
– The WEP pseudo – random number generator is the one that generates this text.
– After the first authentication being successful, a second authentication is carried out for assuring mutual authentication.
– From here the client moves to 2nd state and then to third and the final state.
A WLAN client lying within the coverage area of the network can access the services of the network. Since no obstructions such as floors or ceilings can stop the radio waves, the data can reach the undesired recipients lying near the access points. If there are no stringent security measures, installing a wireless network is same as installing Ethernet ports that can be accessed by anyone by just plugging in to the network. Nowadays a number of WEP attack tools are available such as the AirSnort. These tools can be used by wrong people for exploiting the vulnerabilities of the WEP. Once they get the WEP key, they can use a sniffer tool for viewing the traffic of WLAN once the NIC has been configured properly.