WIRELESS LOCAL AREA NETWORK SECURITY ANALYSIS

ABSTRACT

This research thesis work studied the security settings of Wireless Local Area Network (WLAN), their vulnerability, and alternative solution (s), taken ABU wireless LAN as the case study. The research work present results from a comprehensive trace of wireless network security in a large wireless LAN which is the ABU wireless LAN using two software tools as CommView-for-WiFi for packet capture on the network, and Aircrack-ng for decrypting the encryption found in some Access Points (AP) within the network coverage range.  This has been carried out using the campus-wide network of more than 100 access points (APs) spread over the buildings of the University. Potential problem(s) and appropriate solution(s) which is the use of WPA2 has also been discussed for the improvement of the wireless network in terms of security settings for effective and secure communication putting access control in to cognizance.

TABLE OF CONTENTS

CHAPTER ONE: INTRODUCTION

1.1 Background of the Study ………………………………………………………………….

1.2 Wireless Local Area Networks (WLANS) ……………………………………………

1.3 Types of Wireless Networks …………………………………………………………….

1.3.1 Independent Basic Service Set (IBSS) ……………………………………………..

1.3.2 Basic Service Set (BSS) ………………………………………………………………..

1.3.3 Extended Service Set (ESS) ………………………………………………………….

1.4 Wireless Networking Standards …………………………………………………………

1.5 Problem Definition…………………………………………………………………………

1.6 Link-Layer Security in Local Area Networks ……………………………………….

1.7 Security in Wired LANS ……………………………………………………………………

1.7.1 Challenges in Wireless Security ………………………………………………………

1.8 Research Motivations ………………………………………………………………………

1.9 Objectives of The Study …………………………………………………………………..

1.10 Research Methodology……………………………………………………………………

1.11 Contribution to Knowledge ……………………………………………………………….. 

1.12 Organization of the Thesis…………………………………………………………………. 

CHAPTER TWO: LITERATURE REVIEW

2.1 Definition of Terms………………………………………………………………………….

2.1.1 Base Station ………………………………………………………………………………… 

2.1.2 Client Stations ……………………………………………………………………………… 

2.1.3 Satellite (VSAT) …………………………………………………………………………..

2.1.4 Modem ………………………………………………………………………………………

2.2 Review of Related Literature……………………………………………………………..

2.3 The Challenge of Wireless LAN Security…………………………………………….. 

2.4 Risks and Vulnerabilities of Wireless LANS ………………………………………… 

2.4.1 The Nature of the Wireless Medium ………………………………………………… 

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2.4.2 Insecure Wireless LAN Devices ……………………………………………………… 

2.4.3 Insecure Access Points …………………………………………………………………..

2.4.4 Insecure User Stations …………………………………………………………………… 

2.5 IEEE 802.11 Security Features …………………………………………………………… 

2.5.1 Service Set Identifier (SSID) ………………………………………………………….. 

2.5.2 Wired Equivalent Privacy (WEP) ……………………………………………………. 

2.5.3 MAC Address Filters…………………………………………………………………….. 

2.6 Intrusion Methods Used By Hackers …………………………………………………… 

2.6.1 Invasion & Resource Stealing………………………………………………………….

2.6.2 Traffic Redirection ……………………………………………………………………….. 

2.6.3 Denial of Service (DOS) ……………………………………………………………….. 

2.6.4 Rouge Access Point (Fake AP) ………………………………………………………..

2.7 Security Concerns on IEEE 802.11 Network (Interlink Networks, 2002) …… 

2.7.1 MAC Addresses Authentication………………………………………………………. 

2.7.2 One-Way Authentication ……………………………………………………………….. 

2.7.3 Static WEP-Keys …………………………………………………………………………..

2.7.4 Service Set Identifier (SSID) ………………………………………………………….

2.7.5 WEP Key Vulnerability …………………………………………………………………

CHAPTER THREE: AN EMPERICAL STUDY OF ABU WIRELESS NETWORK

3.1 Introduction …………………………………………………………………………………….

3.2 IEEE802.11 Standard Used By ABU WLAN ……………………………………….. 

3.2.1 IEEE 802.11 a ……………………………………………………………………………… 

3.2.2 IEEE 802.11 b | g …………………………………………………………………………. 

3.2.3 IEEE 802.11 b | g versus IEEE 802.11a ………………………………………….. 

3.3 ABU Wireless LAN Deployment ……………………………………………………….. 

3.3.1 ABU-Zaria Wireless Network Layout ……………………………………………… 

3.3.2 Senate West Base Station ………………………………………………………………. 

3.3.3 Senate East Base Station ……………………………………………………………….. 

3.3.4 Senate North Base Station ……………………………………………………………… 

3.4 Signal Flow across the Network for Internet Access ………………………………. 

3.4.1 Main Base – Station ………………………………………………………………………

3.4.2 General Over View of Signal Flow on The Network …………………………..

3.5 ABU WLAN Network Security…………………………………………………………..

3.5.1 Security at Application Level …………………………………………………………

3.5.2 Security at the Network Level ……………………………………………………….

3.6 Compromising the Network Security (Hacking) …………………………………..

3.6.1 Software Tool for the Hacking ………………………………………………………

3.6.2 Commview for Wi-Fi ……………………………………………………………………

3.6.3 Aircrack-ng ………………………………………………………………………………….

3.7 Steps for a Successful Hacking ……………………………………………………………….

3.8 Resulting Hacking on the Network …………………………………………………….

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CHAPTER FOUR: ANALYSIS AND DISCUSSION OF OUR PROPOSED

SECURITY MECHANISM

4.1 Wi-Fi Protected Access 2 (WPA2) …………………………………………………….

4.2 Introduction ……………………………………………………………………………………. 

4.3 Components Overview for WPA and WPA2 Implementations ………………… 

4.4 WPA2 Features and Benefits……………………………………………………………… 

4.4.1 WPA ………………………………………………………………………………………….. 

4.4.2 WPA2 ………………………………………………………………………………………… 

4.5 Enterprise and Personal Modes for WPA2 …………………………………………… 

4.5.1 WPA AND WPA2 Enterprise Mode ……………………………………………….. 

4.5.2 WPA AND WPA2 Personal Mode ………………………………………………….. 

4.6 Protection from Network Attacks with WPA2 ………………………………………. 

4.7 Enterprise Mode Components for a Secure Environment ………………………… 

4.7.1 Client Adapter (NIC)…………………………………………………………………….. 

4.7.2 Client Supplicant ………………………………………………………………………….. 

4.7.3 EAP Authentication Types …………………………………………………………….. 

4.7.4 Access Points ………………………………………………………………………………. 

4.7.5 Authentication Server/Database ……………………………………………………… 

4.8 WLAN Authentication and Encryption Methods …………………………………… 

4.8.1 Static WEP and Dynamic WEP with IEEE 802.1x …………………………….. 

4.8.2 How WPA2 Authentication Works………………………………………………….. 

4.8.3 How WPA2 Encryption with AES Works ………………………………………… 

4.9 WPA2 Security Advantage ……………………………………………………………….. 

4.10 Steps and Tools for WPA2 Deployment ………………………………………………. 

4.10.1 Introduction ………………………………………………………………………………… 

4.10.2 Seven Steps to Prepare For WPA Or WPA2 Deployment ……………………. 

4.10.3 Step 1—Security Mechanism and Credentials …………………………………… 

4.10.4 Step 2—User Authentication Database …………………………………………….. 

4.10.5 Step 3—Client Operating Systems ………………………………………………….. 

4.10.6 Step 4—Supplicants ……………………………………………………………………..

4.10.7 Step 5—EAP Types ……………………………………………………………………… 

4.10.8 Step 6: Authentication Server …………………………………………………………. 

4.10.9 Step 7: Access Points and Client NIC Cards ………………………………………

4.11 Examples of WPA2 Deployment Configurations…………………………………… 

4.11.1 Windows Deployment of WPA2 Wireless Encryption …………………….. 

4.12 Simulated Instance for the WPA2 Deployment ……………………………………..

CHAPTER FIVE: SUMMARY, CONCLUSION AND RECOMMENDATION

5.1 Summary ……………………………………………………………………………………….. 

5.2 Conclusion ……………………………………………………………………………………… 

5.3 Recommendation ……………………………………………………………………………..

5.4 Future Work…………………………………………………………………………………….

References ……………………………………………………………………………………………

CHAPTER ONE

 INTRODUCTION

1.1     Background of the Study        

1.2     Wireless Local Area Networks (WLANS)

A wireless LAN (WLAN) is analogous to a wired LAN with radio waves being the transport medium instead of traditional wired structures. This allows the users to move around in a limited area while being still connected to the network. Thus, WLANS combine data connectivity with user mobility, and, through simplified configuration, enable movable LANs

(WLAN Association, 1999). In other words, WLANS provide all the functionality of wired LANs, but without the physical constraints of the wire itself.

Generally a WLAN (in Infrastructure mode) consists of a central connection point called the Access Point (AP). It is analogous to a hub or a switch in traditional star topology based wired local area networks. The access point transmits the data between different nodes of a wireless local area network and in most cases serves as the only link between the wireless LAN and the wired LAN. A typical access point can handle some handsome amount of users within a radius of about 300 feet. The wireless nodes, also called clients of a WLAN usually consist of Desktop PCs, Laptops or PDAs equipped with wireless interface cards.

1.3     Types of Wireless Networks

The 1999 version of the 802.11 standard (John et al., 2001) defines the following three types of wireless networks:

1.3.1 Independent Basic Service Set (IBSS)

IBSS commonly referred to as Ad Hoc network, is logically comparable to a Peer-to-Peer network in case of a wired LAN as shown in Fig. 1.1. In case of IBSS different end nodes communicate without any Access Point and thus without any connection to a wired network. It is used to quickly set up a wireless network (to avoid the hidden node problem[2]) such as for a group meeting or at a convention center or at an airport, etc. 

1.3.2 Basic Service Set (BSS)

BSS which is commonly referred to as an infrastructure network consists of a single Access Point as shown in Fig. 1.2. All the communication between any two nodes has to pass through the AP. The coverage area is greatly increased as compared to an IBSS.

1.3.3 Extended Service Set (ESS)

An ESS consists of multiple BSSs each having a single Access Point. Access Point in each BSS is connected to a distribution system that is usually a Wired Ethernet Network.

1.4     Wireless Networking Standards 

Institute of Electrical and Electronics Engineers (IEEE) (WLAN Association, 2002) has specified various WLAN standards. Some important standards in the context of this thesis are summarized in Table 1.1.

Table 1.1   IEEE WLAN Standards

Standard

Description

Approved

IEEE 802.11

Data rates up to 2Mbps in 2.4-GHz ISM band

July 1997

IEEE 802.11a

Data rates up to 54Mbps in 5-GHz UNII band

Sept 1999. End user pr oducts began shipping in early 2002

IEEE 802.11b

Data rates up to 11Mbps in 2.4-GHz ISM band

Sept 1999. End user products began shipping in early 2000

Other standards are the following:

IEEE 802.11g:

In 2002 and 2003, WLAN products supporting a newer standard called 802.11gemerged in the market. 802.11g attempts to combine the best of both 802.11a and 802.11b. 802.11g supports bandwidth up to 54 Mbps, and it uses the 2.4 GHZ frequency for greater range. 802.11g is backwards compatible with 802.11b, meaning that 802.11g access points will work with 802.11b wireless network adapters and vice versa.

IEEE 802.11n:

The newest IEEE standard in the WiFi category is 802.11n. It was designed to improve on 802.11g in the amount of bandwidth supported by utilizing multiple wireless signals and antennas (called MIMO[4]technology) instead of one. When this standard is finalized, 802.11n connections should support data rates of over 100 Mbps. 802.11n also offers somewhat better range over earlier WiFi standards due to its increased signal intensity. 802.11n equipment will be backward compatible with 802.11g gear.

1.5     Problem Definition

Ubiquitous network access without wires is the main attraction underlying wireless network deployment. Although this seems as enough attraction, there exists other side of the picture.

Before going all Wireless an organization should first understand how wireless networks could be vulnerable to several types of intrusion methods used by intruder[5] on a network.

The literatures studied do not offer an experimental evaluation of link-layer security in heavily utilized and congested wireless networks such as the ABU wireless network. We believed that gaining a deep understanding of the real-world security features at the link layer in congested networks is important. The insight can help in the design of robust protocols and implementations to handle attacks from intruders, and other related problems more effectively. 

This thesis focused on one aspects of network security, which is the access control at link layer with respect to ABU wireless LAN. Potential problems and appropriate suggestions will be made. In this thesis we will focus on access control at the link layer, i.e., the procedure used by devices to convince the network that their packets should be forwarded.

Link-layer services may be vulnerable to a large class of denial-of-service attacks based on identity spoofing. This happens because some security services identify clients (users) using only their MAC addresses, which can be easily forged. For example, an attacker in an IEEE 802.11 network can disrupt service to well-behaved clients by spoofing their addresses or the addresses of their access points and requesting disconnection.

Our preliminary findings will be to propose that link-layer can be used to provide an effective security feature in a WLAN based on access control.

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