Wireless Network Security Survey

A Survey of Security in Wireless Networks
Edman G. H Zayzay
Villanova University
Department of Electrical Engineering
800 Lancaster Avenue. Villanova, PA 19085
Phone: (484) 442 -0543. Email: [email protected]

Abstract
The vulnerability of the safety of Wireless Local Area Networks (WLAN) is one of the biggest
disadvantages of a wireless network. The integration of smart card or a crypto memory to a WLAN
device as a repository for all information like certificates, keys, and other credentials, has provided some
level of security in wireless network. However, with the emergence of various devices with wireless
capabilities, it is not always possible to use smart cards and/or crypto memory to provide security in
wireless networks. In particular, with the frequent changes in wireless network topology such as Wireless
Mesh Network (WMN) and Wireless Senor Networks, it is necessary to design an efficient security
scheme for the transfer of data throughout the network. Many approaches have been proposed to
overcome the security challenges in various wireless networks. In this paper, we give an overview of
existing proposals, explain their key ideas and provide some of the advantages and disadvantages of the
proposed schemes.

Index Terms
Wireless, Security, Sensor, Messages, Mesh, Access Point, Base Station, , Distributed System, energyefficiency, multi-path, encryption, decryption

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1. Introduction
There are two characteristics of wired LAN that are not inherent in wireless LAN. Firstly, in order to
transmit over a wired LAN, an endpoint must be physically connected to the LAN. On the other hand,
with a wireless LAN, any station within radio range of the other devices on the LAN can transmit. In a
sense, there is a form of authentication with a wired LAN in that it requires some positive and presumably
observable action to connect a station to a wired LAN.

Secondly, in order to receive a transmission from a station that is part of a wired LAN, the receiving
station must also be attached to the wired LAN. On the other hand, with a wireless LAN, any station
within radio range can receive. Thus wired LAN provides some degrees of privacy, limiting reception of
data to stations connected to the LAN. These differences between wired and wireless LAN suggest the
increased need for robust security services and mechanisms for wireless LAN.

The original 802.11 specification included a set of security features for privacy and authentications that
were quite weak. For privacy, 802.11 defined Wired Equivalent Privacy (WEP) algorithm. The privacy
portion of then802.11 contained a major weakness. Subsequent to the development of WEP, 802.11i task
group has developed a set of capabilities that to address the WLAN security issues. In order to accelerate
the introduction of strong security into WLANs, the Wi-Fi Alliance promulgated Wi-Fi Protected Access
(WPA) as a Wi-Fi Standard. WPA is a set of security mechanisms that eliminates most of the 802.11
security issues and was based on the current state of the 802.11i standard. The final form of the 802.11i
standard is referred to as Robust Security Network (RSN).

Section II of this paper looks at some of the security issues and threats models that are faced in wireless
networks. In this section, consideration is given to Wireless Sensor Networks (WSM) and Wireless Mesh
Networks (WMN). Some of the proposed solutions to address the threats in these networks are explained.
Section III addresses some of the proposed energy efficient algorithms and data encryptions for wireless
networks. Meanwhile we also address in section IV; some of the limitations in sensors and mesh networks
and why traditional encryption-decryption schemes needs to be enhanced for these kinds of wireless
networks. We then provide our conclusion and references in section V and VI respectively.

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2. Security issues and threat models in Wireless Networks
Wireless communications are difficult to protect; they are by nature a broadcast medium. In a broadcast
medium, adversaries can easily eavesdrop on, intercept, inject and alter transmitted data. Most of the
threats and attacks against wireless networks are similar to their wired counterparts while some are
exacerbated with the inclusion of wireless connectivity. In addition, adversaries can interact with the
network from a distance by using expensive radio transceivers and powerful workstations. There are
different types of wireless networks that have varying degrees of applications and threats. In this section,
we consider some of the security issues and threats models encounter in wireless sensor networks and
wireless mesh networks while drawing some comparison to ad hoc mobile networks.

2.1.

Wireless Sensor Networks (WSN) Security issues and threats

Wireless Sensor Networks (WSN) are emerging as both and important new tier in the IT ecosystem and a
rich domain of active research involving hardware and system design, networking, distributed algorithms,
programming models, and security and social factors [1], [2], [3]. The basic idea of sensor network is to
disperse tiny sensing devices; which are capable of sensing some changes if incidents/parameters and
communicating with other devices over a specific geographic area form some specific purpose like target
tracking, surveillance, environmental monitoring etc. Sensor networks are typically characterized by
limited power supplies, low bandwidth, small memory sizes and limited energy. This leads to a very
demanding environment to provide security. Public-key cryptography is too expensive to be usable, and
even fast symmetric-key cipher must be sparingly used.
Adversaries can repeatedly send packets to drain the nodes’ batteries and waste network bandwidth. Since
sensors networks will be deployed in a variety of physically insecure environments, adversary can steal
nodes, recover cryptographic material and pose as authorized nodes in the network. The figure below
demonstrates some of the securities vulnerabilities and threats in sensor networks from [2].

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2.2.
Wireless Mesh Network (WMN) Security issues and threats
Security in Wireless Mesh Network is still in its infancy, [8]. Wireless mesh networks has appeared as a
new and promising wireless networking environment for the next generation of wireless networks. It
facilitates quick and easy extension of local area networks into a large-scale wide area networks. Typical
mesh networks consist of mesh routers and mesh clients. The mesh routers, which are static and powerenabled, form a wireless backbone of the WNMs and interwork with the wired networks to provide multihop wireless internet connectivity to the mesh clients. Mesh clients access the network through mesh
routers. They can also directly mesh with each other. Unlike mesh routers, the mesh clients can be
battery-operated mobile nodes. The work in [8] states that WMS are anticipated to resolve the limitations
and to significantly improve the performance of ad hoc networks, WLANs, WPANs and wireless
metropolitan area networks.

Figure 2: Infrastructure of Wireless Mesh Network, from [8]

There are a great number of potential applications scenarios for wireless mesh networks ranging from
home and communities to high speed MANs. WMN are undergoing rapid commercialization in many
application scenarios such as home networking, intelligent power grids, intelligent transport system and
enterprise networking. Clearly, security in a WMN is extremely important for the effective of these
application areas. One advantage of WMN is that it enables us to integrate various existing networks
through the gateways. However, this benefit also brings related vulnerability to security attacks. There are
various kinds of attack is a wireless mesh network. The some of the main type of attack are detailed as
follows:
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

Denial of Service (DOS): The DoS attack is encountered either by accidental failure in the
system or a malicious action. The conventional way to create a DoS attack is to flood any
centralized resource so that it no longer operates correctly or stop working. A distributed DoS
(DDoS) attack is even more sever threat to WMNs. DDoS attack is launched by a group of
compromised nodes who are part of the same network and who collude together to bring the
network down or seriously affect its operation.



Impersonation attack: This attack creates a serious security risk in WMNs. If proper
authentication of parties is not supported, compromised nodes may be able to join the network,
send false routing information, and masquerade as some other trusted nodes. A compromised
node may get access to the network management system of the network; and it may start
changing the configuration of the system as a legitimate user who has special privileges.



Routing attack: Routing attacks in WMNs could be:
Routing table overflow attack – an attacker attempts to create routes to nonexistent nodes with
intention to create enough routes to prevent new routes from being created or to overwhelm the
protocol implementation. This attack could also lead to resource exhaustion or DoS attack.
Wormhole attack – an attacker receives packets at one location in the network and tunnels them
selectively to another location in the network. Then, the packets are resent into the network, and
the tunnel between two colluding attackers is referred to as a wormhole.
Blackhole/sinkhole attack – a malicious node uses the routing protocol to advertise itself as
having the shortest path to the node. In this situation, the malicious node advertises itself to a not
that it wants to intercept the packet.
Byzantine attack – an invalid operation of the network initiated by malicious nodes where the
presence of compromised nodes and the compromised routing are not detected. This attack will
eventually result in severe consequences to the network as the network operation may seem to
operate normal to the other nodes.
Location disclosure attack - this attack reveals something about the structure of the network to
the locations of nodes such as which other nodes are adjacent to the target, or the physical
location of a node.

Therefore, the routing mechanisms of a WMN must be secured. The usual mechanism, to ensure integrity
of data, is using has functions and message digest [2], [8].

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3. Proposed Energy efficient algorithm and data encryption for Wireless Sensor Networks
In conventional networks, message authenticity, integrity and confidentiality are usually achieved by endto-end security mechanism such as SSH, IPSec, or SSL [6] because of the dominant traffic pattern in endto-end communication; intermediate routers only need to view message headers and it is neither necessary
nor desirable for them to have access to message bodies. This is not the case in sensor networks. The
dominant traffic pattern in sensor networks is many-to-one, with many sensor nodes communicating
sensor readings or network events over a multi-hop topology to a central base station. To prune these
redundant messages to reduce traffic and save energy, sensor networks use in- network processing such as
aggregation and duplicate elimination [6].
Since network processing requires intermediate nodes to access, modify, and suppress the content of
messages, it is unlikely to use end-to-end security mechanism between each sensor node and the base
station to guarantee the authenticity, integrity and confidentiality of the messages. As a result of the above
mentioned, one of the proposed energy efficient algorithm from [6] is a link –layer security architecture
for TinySec.
This platform expects the higher level security protocol to rely on the link-layer security architecture as a
primitive. For example, key distribution protocols, some of which utilize public key cryptography, could
use TinySec to create secure pair wise communication between neighboring nodes. One of the way this
method claims to provide energy efficient encryption of data is as follows.
Since CBC mode for encryption with 8-byte block cypher result in cipher-test which is multiple of 8bytes, this may result in message expansion, which increases power consumption. To mitigate this effect,
the TinySec architecture use a technique known as cipher-text stealing to ensure the cipher-text is the
same length as the underlying plaintext. Encrypting data payload of less than 8-bytes will produce a
cipher-text of 8-bytes because cipher stealing requires at least on block of cipher-text.
This cipher-text stealing technique is the technique of altering processing of the last two blocks of
plaintext, resulting in a reordered transmission of the last two ciphered text and no cipher expansion. This
is accomplished by padding the last block (which is possibly incomplete) with high order bits of the
second to last ciphertext block (stealing the cipher text from the second to last block). The last block is
encrypted and the exchanged with the second to the last ciphertext block, which is then truncated to the
length of the final plaintext block, removing the bits that were stolen, resulting in cipher-text of the same
length as the original message size. In all cases, the processing of all but the last two blocks is unchanged.

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4. Limitation of Wireless Sensor and Mesh Networks
In Wireless Sensor Networks and Wireless Mesh Networks, several factors and/or limitations of these
networks nodes has made the design of security procedure more complicated. The ad hoc nature of
sensors networks poses unique challenges with their security and reliability. Resource constrained sensor
nodes in terms of limited memory; low power, limited processing abilities, and low coverage are
vulnerable to intrusion, interception, modification and fabrication. Because of these unique challenges,
traditional security techniques are not enough to meet the security goals of the confidentiality, integrity,
reliability and availability. Some of the limitation facing such network includes:


Physical limitations: Sensor networks deployment nature in public and hostile environments in
many applications makes them highly vulnerable to capture and vandalism. Physical security of
sensor nodes with tamper proof material increases the cost.



Node limitations: A typical sensor node processor is of 4 – 8MHz [3], having 4KB of RAM,
128KB flash and ideally 916MKz of radio frequency. The heterogeneous nature of sensor nodes
is an additional limitation which prevents on security solution. Due to the deployment nature,
sensor nodes would be deployed in environments where they would be highly prone to physical
vandalism.



Network limitations: Besides node limitations, sensor networks bring all the limitations of a
mobile ad hoc network where they lack physical infrastructure, and rely on insecure wireless
media.

Similarly in wireless mesh networks, there are four major constraints,[8] that is also true for any wireless
systems which has mobile clients. These constraints are CPU, battery mobility and bandwidths

5. Conclusion
In summary, the major security implications in wireless networks depend on the type of network and its
application domain. There can be no single security solution that addresses all of the threats and issues
that arises in the different type of wireless network. However, when deploying or designing a wireless
network, there are few core security requirements that must be met to mitigate some hazards. Prominent
amongst these are data integrity, authentication and confidentiality. With the advances being made in
mobile devices and their ability to retain and access large amount of information, one must always be
concern about the vulnerability of the networks the devices are connecting to. Also, since these devices
are normally battery power, there can be no one algorithm is it optimized for efficient energy
consumptions as every wireless network application has varying degree of data that is being processed

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and requires different processing capability. Therefore, an efficient algorithm is specific to its domain of
application and not across the spectrum of every wireless network.

6. References
[1]. W. Stallings, Cryptography and Network Security: Principles and Practice, 5th Edition.
Prentice-Hall Inc. NJ
[2]. Tanveer Zia and Albert Zomaya, “Security Isssues in Wireless Sensor Networks”, IEEE
Wireless Communication and Networking Conference, 2005
[3]. Al-Sakib Khan Pathan, Hyung-Woo Lee, Choong Seon Hong, “Security in Wireless Sensor
Networks: Issues and Challenges”, The 8th International Conference on Advanced
Communication Technology, 2006. ICACT 2006.
[4]. Sung-Chul Jung; Hyoung-Kee Choi, “An Energy-aware routing protocol considering linklayer security in wireless sensor network”, The 11th International Conference on Advanced
Communication Technology, 2009. ICACT 2009,
[5]. Guohoug Cao; Hubaux, J. P; Yongdae Kim; Yanchao Zhang, “Security and Privacy in
emerging Wireless Networks”, IEEE Wireless Communication, 2010. Volume: 17 Issue: 5
[6]. Md. Anisur Rahman, Mitu Kumar Denath, “ An Energy-Efficient Data Security for Wireless
Sensor Network”, The 11th International Conference on Computer and Information
Technology, 2008. ICCIT 2008.
[7]. Koutroubinas, S; Karoubalis, T; Rozos, P.; Nastou, P.; “Enhancing Security in Wireless
Networks”, IEEE International Symposium on Consumer Electrons, 2004, Page(s): 214-218
[8]. Hassan Redwan, Ki-Hyung Kim; “ Survey of Security Requirement, Attacks and Network
Integration in Wireless Mesh Networks”

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