Interface Security In Fixed Wireless Networks Information Technology Essay
The objective of this study was to develop an authentication algorithm, which facilitates mutual authentication on the access network between base stations and the subscriber stations within the 802.16d framework.
The reviewed literature on the wireless authentication algorithms, security theories and also observing the implemented networks, revealed weaknesses of the fixed WiMAX framework. The one way authentication of the subscriber stations by the base station as a weakness was centered on in this study.
The current 802.16d algorithm was re-designed to incorporate pre-entered and stored equipment identity, against which all devices mutually authenticate in determining genuineness.
Network simulations were used in testing and implementing the re-designed algorithm.
The study was carried out by the researcher based on existing fixed WiMAX infrastructures in Kampala central business district in Uganda and the results of the study were used in developing the new authentication algorithm system.
Activities conducted during this project include;
Studying aspects of the existing system, identifying inefficiencies related to access security management - device identity, authentication and key management.
Implementing the new algorithm.
This project presents an effort to develop a mutual authentication algorithm over the fixed WiMAX framework, which will alleviate the shortcomings of the current 802.16d security implementation in place.
Room for further development was also pointed out to incorporate functionalities that have not been included. The main findings of the study were summarized and recommendations were made as part of the final concluding remarks in this report.
I wish to dedicate this entire book to my Love Eva and our Daughter Devine, you have been a great pillar in every aspect of my study, you are much cherished.
May the Good Lord reward you in his time, so abundantly in glory.
God Bless You All!
I acknowledge the Almighty God without whose Grace, I would not have been able to persevere through this work. I am also very grateful to my supervisor Mr. Mirembe P. Drake under whose intellectual guidance, utmost co-operation and support have seen me this far. I am greatly indebted to you.
To my dear parents, Mr. and Mrs. Lubega Muwonge and all my brothers and sisters who have stood with me throughout this time, all your support can not go unnoticed. I will always be very grateful for the exceeding love and devotion you accorded me during this very challenging time, am eternally thankful.
Fellow course mates; Isaac, Sarah and Mike whose encouragement and teamwork was instrumental in sustaining my interest in the report.
All my friends and relatives not mentioned here may the Good Lord who knows our hearts desires and secrets reward you abundantly for your love and truthfulness.
List of Acronyms
CPE Client premises equipment
SS Subscriber Station
BS Base Station
BST Base Station
802.16d IEEE framework for WiMAX standards, release D
802.16e IEEE framework for WiMAX standards, release E
WiMAX Worldwide Interoperability for Microwave Access
GSM Global System for Mobile Communications, also Groupe Spécial Mobile
LAN Local Area Network
WAN Wide Area Network
WLAN Wireless Local Area Network
RF Radio Frequency
EAP Extensible authentication protocol
EAP-TLS EAP Transport Layer Security
EAP-PSK EAP Pre-shared key
EAP-TTLS EAP Tunneled Transport Layer Security
EAP-IKEv2 EAP Internet key exchange version two
EAP-FAST EAP Flexible Authentication via Secure Tunneling
EAP-SIM EAP Subscriber identity module
QoS Quality of Service
SLA Service Level Agreement
RADIUS Remote Authentication Dial In User Service
AAA Authentication, Authorization and Accounting Server
ASN Access Service Network
CSN Connectivity Service Network
EIR Equipment Identity Register
TABLE OF CONTENTS
List of Tables
List of Figures
Information assurance (IA) is about protecting information assets from destruction, degradation, manipulation and exploitation by an opponent. The difficulty with achieving this is that one day a party may be collaborating on a project and therefore needs access to confidential information, and the next day that party may be an opponent .
In 1996, the US Department of Defense defined IA as:
"Actions taken that protect and defend information and information systems by ensuring their availability, integrity, authentication, confidentiality and non repudiation. This includes providing for restoration of information systems by incorporating protection, detection and reaction capabilities."
Systems security is a very important aspect in telecommunications. It is even more critical when wireless systems are used, because it is generally perceived that wireless networks are easier and more prone to attacks than wire line networks.
Information security can be defined as:
"The protection of information against unauthorized disclosure, transfer, modification, and or destruction, whether accidental or intentional."
International Standards organization in BS7799/ISO17799 defines information security as: "The preservation of confidentiality, integrity and availability of information." .
An infrastructure system is defined as a network of independent, mostly privately owned, automated systems and processes that function collaboratively and synergistically to produce and distribute a continuous flow of essential goods and services .
Securing ICT infrastructures and systems calls for a holistic approach, including humans and their operational environment among others. Technology alone can never protect sensitive global information. Security threats can never be countered with only a keyboard. And no amount of software or hardware will ever be as powerful as the people behind it .
It is therefore important to note from the above, that humans are continuously critical in securing the hardware and software systems.
Security architecture is the design artifact describing how the security controls and countermeasures are positioned, and how they relate to the overall information technology architecture. These controls serve the purpose to maintain the system's quality attributes, among them confidentiality, integrity, availability, accountability and assurance.
It is the plan that shows where security measures need to be placed. If the plan describes a specific solution then, prior to building such a plan, it is vital to make a risk analysis. If the plan describes a generic high level design (reference architecture) then the plan should be based on a threat analysis .
The enormous growth and transitions in the industry have seen the introduction of many new technologies to continue delivering robust and better services. The high cost implication of these technical implementations, has forced service providers to find ways of bundling and delivering these services on more integrated infrastructure - in order to keep it cost effective to the end users .
In their quest for Industry dominance, many service providers have built converged wireless infrastructures with the primary focus on accelerated wide coverage and improved throughput volumes; there has been little or no attention to the now critical network security.
Security is a very critical aspect in telecommunications, especially when wireless systems are used, because it is generally perceived that they are easier to attack. 
As a term, "convergence" has been coined by both the telecoms and data communication industries. From a telecoms perspective, it is the expansion of the public switched telephone network (PSTN) to offer many services on the one network infrastructure. For Internet advocates, it is the death of the PSTN as its role is largely replaced by technologies such as voice over IP (VOIP). In reality, the truth lies somewhere in the middle, and it is here that the cellular industry takes the best of both worlds to create an evolved network, where the goal is the delivery of effective services and applications to the end user, rather than focusing on a particular technology to drive them. Besides, the economies of scale and widespread acceptance of IP as a means of service delivery sees it playing a central role in this process" .
As late as 1993 In the United states of America, unauthorized manipulation and or breaching of the Telco and cellular infrastructures was considered a small non-chargeable offence. With the growth and popularity of the mobile phone, market success was informally paged on how secure the system was.
With the continuing security awareness, user's concerns in the assurance of the cellular network services have directly influenced its use.
Much of today's wireless data infrastructures were inspired by the developments in the cellular platforms that we see today. Many of the features, especially weaknesses are as such shared across the technologies.
The GSM forum has been able to centrally coordinate and enshrine security concerns for the cellular industry using the A5/1 and A5/2 series encryption among others.
The wireless Data Technologies have yet to formulate such an umbrella framework that would foster infrastructure security among the different vendors.
These risks and resulting vulnerabilities have continued to damage user's confidence in the infrastructures. The converged services in Data, Video, VoIP and eTV, have a strong security requirement, for their assured usage across the networks. Without which, it is going to be very difficult to popularly develop and use.
In information and communication technology, a network may be defined as a series of points or nodes (computers, routers, switches, access points, printers etc) interconnected by communication paths. Networks can interconnect with other networks and contain sub networks. In this study text, this is used in reference to fixed or cable networks.
Some of the common fixed network configurations include the bus or linear, star, token ring, and mesh topologies. Networks can also be characterized in terms of spatial distance as local area networks (LANs), metropolitan area networks (MAN), and wide area networks (WANs).
A given network can be further characterized by the type of data transmission technology or protocol it uses - transport control protocol (TCP/IP) or Systems Network Architecture (SNA), sequential packet exchange /internet exchange (SPX/IPX) etc; whether it carries voice, data, video or all of these kinds of signals; by who can use the network (public or private); by the nature of its connectivity - switched or non-switched, or virtual connections); and by the types of physical links - optical fiber, coaxial, unshielded twisted pair or wireless based media .
Wireless networks use radio frequency beacons transmitted over the air from an access point or a base station to the client end devices or subscriber stations. The connectivity media is over the air, as long as it is within range and coverage of the transmitted signal .
Information system refers to information technology that is used by people to accomplish a specified organizational or individual objective. Technology may be used in the gathering, processing, storing, and/or dissemination of information, and the users are trained in the use of that technology, as well as in the procedures to be followed in doing so. The specific technologies that collectively comprise information technology are computer technology and data communications technology. Computers provide most of the storage and processing capabilities, while data communications-specifically networks-provide the means for dissemination and remote access of information .
Information systems involve resources that need managing, through controlled access, enforcing compliancy of usage policies, redundancy mechanisms, business continuity policies in place and their routine Audit to ascertain compliancy and current status .
1.1 Industry Background
The Telecom Industry in Uganda is comprised of product portfolios like Internet, e-mail, other converging and data networking related services, from single-user residential and corporate leased lines to wireless broadband Internet connectivity. It includes client VPN (virtual private network) implementation to office networking, campus LAN / WAN design and installation including various network maintenance schemes.
The Industry rolled out the first commercial wireless network in 2000, which was based on the 2.4 GHz unlicensed free public frequency in the ISM band. In 2005, 3.5 GHz based WiMAX and Canopy network technologies were rolled out, running in parallel to the earlier 2.4 GHz platforms. Around the same time, EVO, 3G and CDMA2000 were introduced in the market.
While this has enabled the Industry to deliver business solutions in core data, voice over IP and video services, cost effectively, converging these services on the same infrastructures has introduced varying security vulnerabilities and risks.
WiMAX (Worldwide Interoperability for Microwave Access) was designed to deliver next-generation, high-speed voice and data services and wireless "last-mile" connections that could potentially serve future growth .
WiMAX has grown through various 802.16x generations, as referenced in below table 1. The proposed IEEE 802.16e standard is previewed as more secure compared to the 802.16d which is also more widely deployed.
The proposed 802.16e security features present a complicated and a high cost skill set implication for the implementers and providers. For these and other reasons, it has been easy to leave out the critical security features.
Table .1 IEEE WiMAX Standards
Figure.1 Conceptual framework of a fixed wireless network architecture.
Access Service Network
Connectivity Service Network
1.2 Problem Statement
Mutual authentication between base stations and subscriber stations is not possible under the 802.16d framework. There is no means of pre-determining genuine base stations by the subscriber stations.
This has created a big vulnerable space over the access network air interface, where rogue BST can be connected to by the genuine CPE's.
This research project was intended to investigate avenues of securing the fixed wireless network air interface using mutual authentication of stations.
1.3.1 Main Objectives
To secure the fixed wireless air interface through mutual client device and base station authentication and session encryption at the access network level.
1.3.2 Specific Objectives
Use pre-entered equipment identity register.
Authenticate client devices based on the register.
Authenticate base stations to client devices.
Encrypt air interface sessions.
Simulate air interface security mechanisms.
1.3.3 Research Questions
How are new client systems commissioned onto the network Infrastructure?
How and when are client devices and base stations authenticated on the network Infrastructure?
Are traffic sessions encrypted across the access network air interface?
If so, when and at which point?
1.3.4 Scope of the Study
The study covered the fixed WiMAX data network infrastructure that delivers converged services in the Telecom industry in Kampala central business district in Uganda.
1.4 Targeted Technology
Remote access security: AAA services, RADIUS
Network Access control
Network simulators - NS tools
Embedded session encryption
1.5 Justification and Significance of the Study
There is a large installed base of 802.16d infrastructures within the telecom industry in Uganda. Service providers are reluctant to upgrade to a more envisaged secure 802.16e framework just for the "sake of security", which incidentally is given a low rate consideration.
The study enabled modifying the 802.16d fixed wireless algorithm, to enhance air interface security through mutual authentication of base stations and subscriber stations.
This is expected to yield the following benefits to the industry;
Enhanced protection of the air interface for the fixed wireless networks, regardless of the technology vendor.
This will foster vendor collaboration in the industry, from a security perspective.
Inculcate better client confidence in the service provider's network security.
A secure network will result into more robust performance for the converged services.
Threats and prospects of legal actions to the industry will be substantially mitigated.
1.6 Proposed Knowledge Contribution of the Study
Another means of securing the air interface in fixed wireless networks will be explored.
Assurance is a single concept that embodies a trinity of Information and Communication Technology (ICT) security requirements: confidentiality, integrity and availability. Confidentiality represents protection from disclosure to unauthorized parties or the disclosure to nominally authorized parties at the wrong time. Integrity means that data are free from corruption, changes, or deletions both intentional and accidental. Availability refers to data or systems being up and running as required /anticipated, and also the property of delivering information at necessary speeds and in the correct sequence. Together, these properties represent the sensitivity requirements of a given system, application, process, or data set. Assurance is the degree of confidence an entity has, that the properties of confidentiality; integrity and availability are being supported .
Without assurance over the air interface, convergence of telecommunications onto a single IP carrier is a technical possibility but a business fantasy. Convergence will not be achieved without a comprehensive ability to apply and maintain assurance in the components, applications and data resident and connected to the converged network , .
2.1 Fixed WiMAX Networks
WiMAX like all wireless networks uses radio frequency beacons to transmit and receive traffic over the air. The broadcast nature of the signal means that it can reach and be received by any node within that frequency [1, 10].
Unlike fixed or cable networks that require physical connectivity to access resources, wireless networks by nature of their signal propagation, can be accessed by anyone within range regardless of authenticity. On this basis, it is imperative that a comprehensive security means is used to authenticate network devices and or users .
2.1.1 Fixed WiMAX - 802.16d Architecture: Features and Application
Can be configured for Wireless Metropolitan Area Network (WMAN)
Easily used for standard Broadband Wireless Access (BWA)
Last mile connectivity
Range up to 50 km.
Provides high speed connectivity that supports multi streams of data, voice and video
Fast deployment and cost saving
Variably can be configured either:
As a point to point backhaul link or
Point to multi-point as a last mile solution, Ref. Fiure. 2.
Point to Point connections are often used for backhaul configurations between base stations in propagating the infrastructure network.
Figure 2 Fixed WiMAX 802.16d Architecture: (Conceptual)
Figure 3 Fixed WiMAX 802.16d Architecture: (Air Interface)
2.1.2 Fixed WiMAX - 802.16d Security Architecture
2.1.2a The 802.16d Authentication Process
Security Association (SA) is composed of an encryption algorithm, Security Information (keys, certificates and versions, etc) Identified by SA I.D
The security process involves three aspects;
2 Data Key Exchange
3 Data Privacy
2.1.2b Analyzing the 802.16d Authentication Process
Subscriber station is authenticated using its X.509 certificate.
There is No Base station authentication to the subscriber stations.
There are Negotiated security capabilities between BS and SS
Security association identity (SAID) is established.
Authentication Key (AK) is (are) exchanged
The AK serves as an authorization token for further infrastructure access
The AK is encrypted using public key cryptography
Authentication is completed when both SS and BS possess AK
Weaknesses of the 802.16d Authentication Process
There is No mutual authentication between the BS and the SS.
Subscriber station certification offers a limited authentication method in the process.
A new authentication method requires adding new type of authentication message
Figure 4 Fixed WiMAX 802.16d Security Architecture concept
C:\Users\Nkangi1\Pictures\Fixed WiMAX 802.16d Security Architecture.jpg
2.1.3 Fixed WiMAX 802.16d Authentication Methods and Algorithms
2.1.3a PPP Authentication Protocol
2.1.3b The Extensible Authentication Protocol (EAP)
2.1.3c Mac Address based Authentication
2.2 Security by Design
Computer security technologies are based on logic. Security is extraneous to the function of a computer application, rather than ancillary to it, therefore security necessarily imposes restrictions on the application's behavior .
There are several approaches to security in computing, sometimes used in combination for validity:
Trust all the system to abide by a security policy but the system is not trustworthy.
Trust all the system to abide by a security policy and the system is validated as trustworthy.
Trust no system but enforce a security policy with mechanisms that are not trustworthy.
Trust no system but enforce a security policy with trustworthy mechanisms.
Many systems have unintentionally resulted in the first possibility. Since approach two is expensive and non-deterministic, its use is very limited. Approaches one and three, lead to failure. Because approach number four is often based on hardware mechanisms and avoids abstractions and a multiplicity of degrees of freedom, it is more practical. Combinations of approaches two and four are often used in a layered architecture with thin layers of two and thick layers of four .
There are various strategies and techniques used in designing security systems. There are few, if any, effective strategies to enhance security after design.
One technique enforces the "principle of least privilege" to a great extent, where an entity has only the privileges that are needed for its function. That way even if an attacker gains access to one part of the system, fine-grained security ensures that it is just as difficult for them to access the rest , .
Furthermore, by breaking the system up into smaller components, the complexity of individual components is reduced, opening up the possibility of using techniques such as automated theorem to prove the correctness of crucial software subsystems. This enables a "closed form solution" to security that works well when only a single well-characterized property can be isolated as critical, and that property is also assessable to math. It is impractical for generalized correctness, which probably can never be defined or proven. Where formal correctness proofs are not possible, rigorous use of code review and unit testing, represent a best-effort approach to make modules secure.
The design should use "defense in depth", where more than one subsystem needs to be violated to compromise the integrity of the system and the information it holds. Defense in depth works well when the breaching of one security measure does not provide a platform to subvert another.
Also, the cascading principle acknowledges that several low hurdles do not make a high hurdle. So cascading several weak mechanisms does not provide the safety of a single stronger mechanism .
Subsystems should default to secure settings, and wherever possible should be designed to "fail secure" rather than "fail insecure". Ideally, a secure system should require a deliberate, conscious, knowledgeable and free decision on the part of legitimate authorities in order to make it insecure.
The designers and operators of systems should assume that security breaches are inevitable. Full audit trails should be kept for system activity, so that when a security breach occurs, the mechanism and extent of the breach can be determined. Storing audit trails remotely, where they can only be appended to, may keep intruders from covering their tracks. Finally, full disclosure helps to ensure that when bugs are found the "window of vulnerability" is kept as short as possible .
Unfortunately, most installed fixed wireless infrastructure base, has no in built access network security or better called air interface security by default. Therefore this security framework cannot be applied here.
2.3 Security Architecture
Security provided by IT Systems can be defined as the system's ability to protect confidentiality and integrity of processed data, as well as to be able to provide availability of the system and data.
"IT Architecture" may be defined as a set of design artifacts, which are relevant for describing an object such that it can be produced to requirements as well as maintained over the period of its useful life. The design artifact describes the structure of components, their inter-relationships, and the principles and guidelines governing their design and evolution over time .
IT Security Architecture may be defined as;
The design artifacts that describe how the security controls (countermeasures) are positioned and how they relate to the overall IT Architecture. These controls serve the purpose to maintain the system's quality attributes, among them confidentiality, integrity and availability.
Security qualities are often considered as "non-functional" requirements when systems are designed. In other words they are not required for the system to meet its functional goals such as processing financial transactions, but are needed for a given level of assurance that the system will perform to meet the functional requirements that have been defined .
In recent years, there has been a trend towards a hierarchy of control objectives, controls and specific technical implementations of controls, which are implemented within a given security architecture in order to meet the security requirements.
The architecture of 802.16d platforms bears no such inherent security designs. There is no mutual authentication between subscriber stations and the base stations and besides, the air interface transport is vulnerable to man in the middle attacks.
2.3 Information Security Managed Services
This involves outsourcing parts or all of the system security functions of the organization to a third party service provider, to manage it.
Information security managed services (ISMS) is an example of applying the management system conceptual model to the discipline of Information Security. Unique attributes to this instance of a management system include:
Risk management applied to information and based upon metrics of confidentiality, integrity, and availability
Total quality management (TQM) applied to information security processes and based upon metrics of efficiency and effectiveness.
A monitoring and reporting model based upon abstraction layers that filter and aggregate operational details for management presentation.
A structured approach towards integrating people, process, and technology to furnish enterprise information security services.
An extensible framework from which to manage information security compliance.
An ISMS brings structure to the information security program. With clear direction and authorization, roles are understood. Defined functions or services allow derivation of tasks that can be delegated. Metrics can be collected and analyzed, producing feedback for "continuous process improvement" .
In many situations, creation of an information security management system inspires and spawns complementary management systems in other disciplines such as human resources, physical security, business continuity, and more. The framework and management system principles transcend disciplines, and tend to enhance multi-disciplinary interoperation .
Benefits of Managed Security Services:
Enables utilizing of the highly skilled labour from the service provider, for effective solutions.
Cost effective service provision, initially negotiated fixed cost, minus operational over heads.
Problems of Managed Security Services:
Uncertainty of confidentiality, especially when entrusting ICT assets with third parties.
It has been argued by many I.S security scholars that the strongest element in information security framework lies within the users. This is very problematic to implement and control under managed approach, with third party users.
Besides, managed services can only be useful within fixed WiMAX frameworks, if there existed in built security features in the 802.16d algorithm to address the identified concerns. These would therefore have been activated by the managed service provider.
2.4 Defense in Depth
Defense-in-Depth is a layered protection scheme for critical information system components. This strategy comprises the following areas;
Defending the network and infrastructure
Defending the enclave boundary
Defending the computing environment
The term enclave as used in the Defense in depth protection strategy refers to a "collection of computing environments connected by one or more internal networks under the control of a single authority and security policy, including personnel and physical security. Enclaves always assume the highest task assurance category and security classification of the automated information system processes they support and derive their security needs from such systems.
They provide standard information assurance capabilities such as boundary defense, incident detection and response and key management. Enclaves may be specific to an organization or a mission, and the computing environments may be organized by physical proximity or by function independent of location. Examples of enclaves include local area networks (LANs) and the applications they host, backbone networks, and data processing centers. For instance, the U.S. federal and defense computing environments can be categorized as public, private, or classified .
The Defense-in-Depth strategy is built on three critical elements: people, technology, and operations.
Network security revolves around the three key principles of confidentiality integrity and availability (CIA). Depending upon the application and context, one of these principles might be more important than the others. For example, an organization would encrypt an electronically transmitted classified document to prevent an unauthorized person from reading its contents.
Thus, confidentiality of the information is paramount. If an individual succeeds in breaking the encryption cipher and, then, retransmits a modified encrypted version, the integrity of the message is compromised. On the other hand, an organization such as Amazon would be severely damaged if its network were out of operation for an extended period of time. Therefore, availability is a key concern of such e-commerce companies .
Confidentiality is concerned with preventing the unauthorized disclosure of sensitive information. The disclosure could be intentional, such as breaking a cipher and reading the information, or it could be unintentional, due to carelessness or incompetence of individuals handling the information.
There are three goals of integrity;
Prevention of the modification of information by unauthorized users
Prevention of the unauthorized or unintentional modification of information by authorized users
Preservation of the internal and external consistency;
Internal consistency ensures that internal data is consistent. For example, in an organizational database, the total number of items owned by an organization must equal the sum of the same items shown in the database as being held by each element of the organization.
External consistency ensures that the data stored in the database is consistent with the real world. Relative to the previous example, the total number of items physically sitting on the shelf must equal the total number of items indicated by the database.
Availability assures that a system's authorized users have timely and uninterrupted access to the information in the system and to the network.
Defense in depth strategy is defined to defend against the following types of attacks
2.4.1 Passive, Active, Close-In, Insider, and Distribution
Passive attacks include traffic analysis, monitoring of unprotected communications, decrypting weakly encrypted traffic, and capture of authentication information (such as passwords). Passive intercept of network operations can give adversaries indications and warnings of impending actions. Passive attacks can result in disclosure of information or data files to an attacker without the consent or knowledge of the user. Examples include the disclosure of personal information such as credit card numbers and medical files.
Active attacks include attempts to circumvent or break protection features, introduce malicious code, or steal or modify information. These attacks may be mounted against a network backbone, exploit information in transit, electronically penetrate an enclave, or attack an authorized remote user during an attempt to connect to an enclave. Active attacks can result in the disclosure or dissemination of data files, denial of service, or modification of data.
Close in attacks consist of individuals attaining physical proximity to networks, systems, or facilities for the purpose of modifying, gathering, or denying access to information. Close physical proximity is achieved through surreptitious entry, open access, or both.
User or Insider attacks can be malicious or non-malicious. Malicious insiders intentionally eavesdrop, steal, or damage information; use information in a fraudulent manner; or deny access to other authorized users. Non-malicious attacks typically result from carelessness, lack of knowledge, or intentional circumvention of security for such reasons as "getting the job done."
Distribution attacks focus on the malicious modification of hardware or software at the factory or during distribution. These attacks can introduce malicious code into a product, such as a back door to gain unauthorized access to information or a system function at a later date.
2.4.2 Counter Measures to These Attacks
Defense in multiple places where emphasis is put on information protection mechanisms at multiple locations against internal and external threats.
Layered defenses that are deployed in multiple information protection and detection mechanisms so that a threat will have to negotiate multiple barriers to gain access to critical information.
Security robustness based on the value of the information system component to be protected and the anticipated threats, estimation of the robustness of each information assurance components. Robustness is measured in terms of assurance and strength of the information assurance component.
Deploy intrusion detection systems to mitigate intrusions, evaluate information and results, and, where necessary, to take action.
2.4.3 Defense In Depth Implementation
Make information assurance decisions based on risk analysis and keyed to the organization's operational objectives.
Draw from all three facets of defense in depth people, operations and technology.
Technical mitigations are of no value without trained people to use them and operational procedures to guide their application.
Exploit available commercial off the shelf products and rely on in house development for those items not otherwise available.
Periodically assess the IA posture of the information infrastructure.
Technology tools, such as automated scanners for networks, can assist in vulnerability assessments.
Take into account, not only the actions of those with hostile intent, but also inadvertent or careless actions.
Employ multiple means of threat mitigation, overlapping protection approaches to counter anticipated events so that loss or failure of a single barrier does not compromise the overall information infrastructure.
Ensure that only trustworthy personnel have physical access to the system.
Methods of providing such assurance include appropriate background investigations, security clearances, credentials, and badges.
Use established procedures to report incident information provided by intrusion detection mechanisms to authorities and specialized analysis and response centers.
Defense in depth would be the most appropriate security mechanism to address the concerns raise in this study. However this too, will need to work alongside pre-designed and in built security features in the 802.16d wireless framework.
As it stands now, defense in depth modalities as theorized above, would not be implementable.
2.5 Other Security Works
Work in progress
2.6 Existing System Security Operations
The vastly deployed 802.16d framework has a one way authentication mechanism for its access infrastructure security. While the client premises equipment (CPE) also called subscriber stations (SS) are authenticated by the base stations (BST) on accessing the network, The BST's are not authenticated by the connecting CPE's. This has created a possibility of various attacks;
Man in the middle attacks, Rogue BST's could be sniffed into position and connected to by unsuspecting CPE's, exposing the security algorithms used within the infrastructure.
Therefore the existing 802.16d authentication algorithm as used in the fixed wireless (WiMAX) networks cannot meet today's required security challenges.
This chapter describes the research methods and tools employed in conducting the study.
The research explored the underlying access network air interface security authentication methods used within the fixed WiMAX infrastructures, to describe what has been happening and what should be happening. It accords the researcher relevant tools to thoroughly understand and explore the prevailing situation, and facilitate formulating an appropriate solution to the earlier identified research problem.
3.1 Targeted Population
Population refers to the totality of an aspect in whole, intended for use in conducting the study of an identified problem.
The study was conducted within the Telecom Industry, with focus on all the fixed WiMAX infrastructure systems. This is all implemented within the 802.16d framework.
3.2 Methods to be used
First hand data was collected during the study. Routine functions and their operational procedures, system policies were examined. This method is chosen because of below factors;
Easily ascertained whether any security framework existed within the access network air interface.
To ascertain how effective the existing security features and practices are.
Helped gain first hand understanding of how the security framework was handled within the access network infrastructure.
Using this method facilitated the following;
Enabled the researcher gain required information, first hand, truthfully and quickly.
ii. Document Review and Evaluation
The written down policies, procedures and Network design diagrams were reviewed.
Using this method facilitated the following;
Gained better understanding of the existing fixed WiMAX infrastructure designs and precise functions of core components.
How the client service provisioning processes flow.
Ascertained the intended objectives from the existing infrastructure designs.
iii. Network Simulators
These were suggested for use as they present a cost effective way to test the proposed mutual authentication security mechanisms without risking the live production networks.
Besides, the cost requirements for the appropriate equipment to present acceptable test environment are prohibitively high.
3.3 Tools Used
Network Simulators - NS2
3.4 Algorithm Re-Design - 802.16d Fixed WiMAX.
During this stage, the existing system framework that needed to be changed was appropriately modified.
Work In Progress
3.5.1 Technology Considerations
In realizing the study objectives, below technologies used;
i. Perimeter - Access network.
â€¢ Mutual device authentication - CPE's and Base Stations.
â€¢ Session encryption
ii. Network - Core Connectivity.
â€¢ Equipment identity register
â€¢ Network access control framework
â€¢ Mandatory access control /user authentication - AAA /Radius
PRESENTATION of RESULTS
Work In Progress
4.1 Weaknesses of 802.16d Authentication Methods and Algorithms
4.1.1 PPP Authentication Protocol
4.1.2 The Extensible Authentication Protocol (EAP)
4.1.3 Mac Address based Authentication
4.2 Modification of the 802.16d Authentication Algorithm
4.2.1 Identified variables currently used in the 802.16d Algorithm
4.2.2 The modified algorithm - Authentication flow
CONCLUSION and RECOMMENDATION
5.1 The Conclusion
Work In Progress
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