Ch07NetSec6e_accessiblePPT.pptx

Network Security Essentials: Applications and Standards

Sixth Edition

Chapter 7

Wireless Network Security

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There are application-specific security mechanisms for a number of application

areas, including electronic mail (S/MIME, PGP), client/server (Kerberos), Web access

(Secure Sockets Layer), and others. However, users have security concerns that

cut across protocol layers. For example, an enterprise can run a secure, private IP

network by disallowing links to untrusted sites, encrypting packets that leave the

premises, and authenticating packets that enter the premises. By implementing security

at the IP level, an organization can ensure secure networking not only for

applications that have security mechanisms but also for the many security-ignorant

applications.

IP-level security encompasses three functional areas: authentication, confidentiality,

and key management. The authentication mechanism assures that a received

packet was, in fact, transmitted by the party identified as the source in the packet

header. In addition, this mechanism assures that the packet has not been altered in

transit. The confidentiality facility enables communicating nodes to encrypt messages

to prevent eavesdropping by third parties. The key management facility is concerned

with the secure exchange of keys.

We begin this chapter with an overview of IP security (IPsec) and an introduction

to the IPsec architecture. We then look at each of the three functional areas in

detail. Appendix D reviews Internet protocols.

Wireless Security (1 of 2)

Some of the key factors contributing to the higher security risk of wireless networks compared to wired networks include:

Channel

Wireless networking typically involves broadcast communications, which is far more susceptible to eavesdropping and jamming than wired networks

Wireless networks are also more vulnerable to active attacks that exploit vulnerabilities in communications protocols

Mobility

Wireless devices are far more portable and mobile than wired devices

This mobility results in a number of risks

Copyright © 2016, 2012, 2009 by Pearson Education, Inc.

All Rights Reserved

Medical Law and Ethics, Fifth Edition

Bonnie F. Fremgen

Copyright © 2017 Pearson Education, Inc. All Rights Reserved

Wireless networks, and the wireless devices that use them, introduce a host of security

problems over and above those found in wired networks. Some of the key factors

contributing to the higher security risk of wireless networks compared to wired

networks include the following [MA10]:

• Channel: Wireless networking typically involves broadcast communications,

which is far more susceptible to eavesdropping and jamming than wired networks.

Wireless networks are also more vulnerable to active attacks that exploit

vulnerabilities in communications protocols.

• Mobility: Wireless devices are, in principal and usually in practice, far more

portable and mobile than wired devices. This mobility results in a number of

risks, described subsequently.

• Resources: Some wireless devices, such as smartphones and tablets, have sophisticated

operating systems but limited memory and processing resources

with which to counter threats, including denial of service and malware.

• Accessibility: Some wireless devices, such as sensors and robots, may be left

unattended in remote and/or hostile locations. This greatly increases their vulnerability

to physical attacks.

2

Wireless Security (2 of 2)

Resources

Some wireless devices, such as smartphones and tablets, have sophisticated operating systems but limited memory and processing resources with which to counter threats, including denial of service and malware

Accessibility

Some wireless devices, such as sensors and robots, may be left unattended in remote and/or hostile locations

This greatly increases their vulnerability to physical attacks

Copyright © 2016, 2012, 2009 by Pearson Education, Inc.

All Rights Reserved

Medical Law and Ethics, Fifth Edition

Bonnie F. Fremgen

Copyright © 2017 Pearson Education, Inc. All Rights Reserved

Figure 7.1 Wireless Networking Components

Copyright © 2017 Pearson Education, Inc. All Rights Reserved

In simple terms, the wireless environment consists of three components that

provide point of attack (Figure 7.1). The wireless client can be a cell phone, a

Wi-Fi–enabled laptop or tablet, a wireless sensor, a Bluetooth device, and so on.

The wireless access point provides a connection to the network or service. Examples

of access points are cell towers, Wi-Fi hotspots, and wireless access points to wired

local or wide area networks. The transmission medium, which carries the radio

waves for data transfer, is also a source of vulnerability.

4

Wireless Network Threats (1 of 4)

Accidental association

Company wireless L A Ns in close proximity may create overlapping transmission ranges

A user intending to connect to one L A N may unintentionally lock on to a wireless access point from a neighboring network

Malicious association

In this situation, a wireless device is configured to appear to be a legitimate access point, enabling the operator to steal passwords from legitimate users and then penetrate a wired network through a legitimate wireless access point

Copyright © 2016, 2012, 2009 by Pearson Education, Inc.

All Rights Reserved

Medical Law and Ethics, Fifth Edition

Bonnie F. Fremgen

Copyright © 2017 Pearson Education, Inc. All Rights Reserved

[CHOI08] lists the following security threats to wireless networks:

• Accidental association: Company wireless LANs or wireless access points to

wired LANs in close proximity (e.g., in the same or neighboring buildings)

may create overlapping transmission ranges. A user intending to connect to

one LAN may unintentionally lock on to a wireless access point from a neighboring

network. Although the security breach is accidental, it nevertheless exposes

resources of one LAN to the accidental user.

• Malicious association: In this situation, a wireless device is configured to appear

to be a legitimate access point, enabling the operator to steal passwords

from legitimate users and then penetrate a wired network through a legitimate

wireless access point.

• Ad hoc networks: These are peer-to-peer networks between wireless computers

with no access point between them. Such networks can pose a security

threat due to a lack of a central point of control.

• Nontraditional networks: Nontraditional networks and links, such as personal

network Bluetooth devices, barcode readers, and handheld PDAs, pose a security

risk in terms of both eavesdropping and spoofing.

• Identity theft (MAC spoofing): This occurs when an attacker is able to eavesdrop

on network traffic and identify the MAC address of a computer with

network privileges.

• Man-in-the middle attacks: This type of attack is described in Chapter 3 in

the context of the Diffie-Hellman key exchange protocol. In a broader sense,

this attack involves persuading a user and an access point to believe that they

are talking to each other when in fact the communication is going through an

intermediate attacking device. Wireless networks are particularly vulnerable

to such attacks.

• Denial of service (DoS): This type of attack is discussed in detail in Chapter 10.

In the context of a wireless network, a DoS attack occurs when an attacker

continually bombards a wireless access point or some other accessible wireless

port with various protocol messages designed to consume system resources.

The wireless environment lends itself to this type of attack, because it is so

easy for the attacker to direct multiple wireless messages at the target.

• Network injection: A network injection attack targets wireless access points

that are exposed to nonfiltered network traffic, such as routing protocol messages

or network management messages. An example of such an attack is

one in which bogus reconfiguration commands are used to affect routers and

switches to degrade network performance.

5

Wireless Network Threats (2 of 4)

Ad hoc networks

These are peer-to-peer networks between wireless computers with no access point between them

Such networks can pose a security threat due to a lack of a central point of control

Nontraditional networks

Personal network Bluetooth devices, barcode readers, and handheld P D As pose a security risk in terms of both eavesdropping and spoofing

Copyright © 2016, 2012, 2009 by Pearson Education, Inc.

All Rights Reserved

Medical Law and Ethics, Fifth Edition

Bonnie F. Fremgen

Copyright © 2017 Pearson Education, Inc. All Rights Reserved

[CHOI08] lists the following security threats to wireless networks:

• Accidental association: Company wireless LANs or wireless access points to

wired LANs in close proximity (e.g., in the same or neighboring buildings)

may create overlapping transmission ranges. A user intending to connect to

one LAN may unintentionally lock on to a wireless access point from a neighboring

network. Although the security breach is accidental, it nevertheless exposes

resources of one LAN to the accidental user.

• Malicious association: In this situation, a wireless device is configured to appear

to be a legitimate access point, enabling the operator to steal passwords

from legitimate users and then penetrate a wired network through a legitimate

wireless access point.

• Ad hoc networks: These are peer-to-peer networks between wireless computers

with no access point between them. Such networks can pose a security

threat due to a lack of a central point of control.

• Nontraditional networks: Nontraditional networks and links, such as personal

network Bluetooth devices, barcode readers, and handheld PDAs, pose a security

risk in terms of both eavesdropping and spoofing.

• Identity theft (MAC spoofing): This occurs when an attacker is able to eavesdrop

on network traffic and identify the MAC address of a computer with

network privileges.

• Man-in-the middle attacks: This type of attack is described in Chapter 3 in

the context of the Diffie-Hellman key exchange protocol. In a broader sense,

this attack involves persuading a user and an access point to believe that they

are talking to each other when in fact the communication is going through an

intermediate attacking device. Wireless networks are particularly vulnerable

to such attacks.

• Denial of service (DoS): This type of attack is discussed in detail in Chapter 10.

In the context of a wireless network, a DoS attack occurs when an attacker

continually bombards a wireless access point or some other accessible wireless

port with various protocol messages designed to consume system resources.

The wireless environment lends itself to this type of attack, because it is so

easy for the attacker to direct multiple wireless messages at the target.

• Network injection: A network injection attack targets wireless access points

that are exposed to nonfiltered network traffic, such as routing protocol messages

or network management messages. An example of such an attack is

one in which bogus reconfiguration commands are used to affect routers and

switches to degrade network performance.

6

Wireless Network Threats (3 of 4)

Identity theft (M A C spoofing)

This occurs when an attacker is able to eavesdrop on network traffic and identify the M A C address of a computer with network privileges

Man-in-the-middle attacks

This attack involves persuading a user and an access point to believe that they are talking to each other when in fact the communication is going through an intermediate attacking device

Wireless networks are particularly vulnerable to such attacks

Copyright © 2016, 2012, 2009 by Pearson Education, Inc.

All Rights Reserved

Medical Law and Ethics, Fifth Edition

Bonnie F. Fremgen

Copyright © 2017 Pearson Education, Inc. All Rights Reserved

[CHOI08] lists the following security threats to wireless networks:

• Accidental association: Company wireless LANs or wireless access points to

wired LANs in close proximity (e.g., in the same or neighboring buildings)

may create overlapping transmission ranges. A user intending to connect to

one LAN may unintentionally lock on to a wireless access point from a neighboring

network. Although the security breach is accidental, it nevertheless exposes

resources of one LAN to the accidental user.

• Malicious association: In this situation, a wireless device is configured to appear

to be a legitimate access point, enabling the operator to steal passwords

from legitimate users and then penetrate a wired network through a legitimate

wireless access point.

• Ad hoc networks: These are peer-to-peer networks between wireless computers

with no access point between them. Such networks can pose a security

threat due to a lack of a central point of control.

• Nontraditional networks: Nontraditional networks and links, such as personal

network Bluetooth devices, barcode readers, and handheld PDAs, pose a security

risk in terms of both eavesdropping and spoofing.

• Identity theft (MAC spoofing): This occurs when an attacker is able to eavesdrop

on network traffic and identify the MAC address of a computer with

network privileges.

• Man-in-the middle attacks: This type of attack is described in Chapter 3 in

the context of the Diffie-Hellman key exchange protocol. In a broader sense,

this attack involves persuading a user and an access point to believe that they

are talking to each other when in fact the communication is going through an

intermediate attacking device. Wireless networks are particularly vulnerable

to such attacks.

• Denial of service (DoS): This type of attack is discussed in detail in Chapter 10.

In the context of a wireless network, a DoS attack occurs when an attacker

continually bombards a wireless access point or some other accessible wireless

port with various protocol messages designed to consume system resources.

The wireless environment lends itself to this type of attack, because it is so

easy for the attacker to direct multiple wireless messages at the target.

• Network injection: A network injection attack targets wireless access points

that are exposed to nonfiltered network traffic, such as routing protocol messages

or network management messages. An example of such an attack is

one in which bogus reconfiguration commands are used to affect routers and

switches to degrade network performance.

7

Wireless Network Threats (4 of 4)

Denial of service (D o S)

This attack occurs when an attacker continually bombards a wireless access point or some other accessible wireless port with various protocol messages designed to consume system resources

The wireless environment lends itself to this type of attack because it is so easy for the attacker to direct multiple wireless messages at the target

Network injection

This attack targets wireless access points that are exposed to nonfiltered network traffic, such as routing protocol messages or network management messages

Copyright © 2016, 2012, 2009 by Pearson Education, Inc.

All Rights Reserved

Medical Law and Ethics, Fifth Edition

Bonnie F. Fremgen

Copyright © 2017 Pearson Education, Inc. All Rights Reserved

[CHOI08] lists the following security threats to wireless networks:

• Accidental association: Company wireless LANs or wireless access points to

wired LANs in close proximity (e.g., in the same or neighboring buildings)

may create overlapping transmission ranges. A user intending to connect to

one LAN may unintentionally lock on to a wireless access point from a neighboring

network. Although the security breach is accidental, it nevertheless exposes

resources of one LAN to the accidental user.

• Malicious association: In this situation, a wireless device is configured to appear

to be a legitimate access point, enabling the operator to steal passwords

from legitimate users and then penetrate a wired network through a legitimate

wireless access point.

• Ad hoc networks: These are peer-to-peer networks between wireless computers

with no access point between them. Such networks can pose a security

threat due to a lack of a central point of control.

• Nontraditional networks: Nontraditional networks and links, such as personal

network Bluetooth devices, barcode readers, and handheld PDAs, pose a security

risk in terms of both eavesdropping and spoofing.

• Identity theft (MAC spoofing): This occurs when an attacker is able to eavesdrop

on network traffic and identify the MAC address of a computer with

network privileges.

• Man-in-the middle attacks: This type of attack is described in Chapter 3 in

the context of the Diffie-Hellman key exchange protocol. In a broader sense,

this attack involves persuading a user and an access point to believe that they

are talking to each other when in fact the communication is going through an

intermediate attacking device. Wireless networks are particularly vulnerable

to such attacks.

• Denial of service (DoS): This type of attack is discussed in detail in Chapter 10.

In the context of a wireless network, a DoS attack occurs when an attacker

continually bombards a wireless access point or some other accessible wireless

port with various protocol messages designed to consume system resources.

The wireless environment lends itself to this type of attack, because it is so

easy for the attacker to direct multiple wireless messages at the target.

• Network injection: A network injection attack targets wireless access points

that are exposed to nonfiltered network traffic, such as routing protocol messages

or network management messages. An example of such an attack is

one in which bogus reconfiguration commands are used to affect routers and

switches to degrade network performance.

8

Securing Wireless Transmissions (1 of 2)

The principal threats to wireless transmission are eavesdropping, altering or inserting messages, and disruption

To deal with eavesdropping, two types of countermeasures are appropriate:

Signal-hiding techniques

Turn off S S I D broadcasting by wireless access points

Assign cryptic names to S S I Ds

Copyright © 2016, 2012, 2009 by Pearson Education, Inc.

All Rights Reserved

Medical Law and Ethics, Fifth Edition

Bonnie F. Fremgen

Copyright © 2017 Pearson Education, Inc. All Rights Reserved

The principal threats to wireless transmission

are eavesdropping, altering or inserting messages, and disruption. To deal with

eavesdropping, two types of countermeasures are appropriate:

• Signal-hiding techniques: Organizations can take a number of measures to

make it more difficult for an attacker to locate their wireless access points,

including turning off service set identifier (SSID) broadcasting by wireless access

points; assigning cryptic names to SSIDs; reducing signal strength to the

lowest level that still provides requisite coverage; and locating wireless access

points in the interior of the building, away from windows and exterior walls.

Greater security can be achieved by the use of directional antennas and of

signal-shielding techniques.

• Encryption: Encryption of all wireless transmission is effective against eavesdropping

to the extent that the encryption keys are secured.

The use of encryption and authentication protocols is the standard method of

countering attempts to alter or insert transmissions.

The methods discussed in Chapter 10 for dealing with DoS apply to wireless

transmissions. Organizations can also reduce the risk of unintentional DoS attacks.

Site surveys can detect the existence of other devices using the same frequency

range, to help determine where to locate wireless access points. Signal strengths can

be adjusted and shielding used in an attempt to isolate a wireless environment from

competing nearby transmissions.

9

Securing Wireless Transmissions (2 of 2)

Reduce signal strength to the lowest level that still provides requisite coverage

Locate wireless access points in the interior of the building, away from windows and exterior walls

Encryption

Is effective against eavesdropping to the extent that the encryption keys are secured

Copyright © 2016, 2012, 2009 by Pearson Education, Inc.

All Rights Reserved

Medical Law and Ethics, Fifth Edition

Bonnie F. Fremgen

Copyright © 2017 Pearson Education, Inc. All Rights Reserved

The principal threats to wireless transmission

are eavesdropping, altering or inserting messages, and disruption. To deal with

eavesdropping, two types of countermeasures are appropriate:

• Signal-hiding techniques: Organizations can take a number of measures to

make it more difficult for an attacker to locate their wireless access points,

including turning off service set identifier (SSID) broadcasting by wireless access

points; assigning cryptic names to SSIDs; reducing signal strength to the

lowest level that still provides requisite coverage; and locating wireless access

points in the interior of the building, away from windows and exterior walls.

Greater security can be achieved by the use of directional antennas and of

signal-shielding techniques.

• Encryption: Encryption of all wireless transmission is effective against eavesdropping

to the extent that the encryption keys are secured.

The use of encryption and authentication protocols is the standard method of

countering attempts to alter or insert transmissions.

The methods discussed in Chapter 10 for dealing with DoS apply to wireless

transmissions. Organizations can also reduce the risk of unintentional DoS attacks.

Site surveys can detect the existence of other devices using the same frequency

range, to help determine where to locate wireless access points. Signal strengths can

be adjusted and shielding used in an attempt to isolate a wireless environment from

competing nearby transmissions.

10

Securing Wireless Access Points

The main threat involving wireless access points is unauthorized access to the network

The principal approach for preventing such access is the I E E E 802.1x standard for port-based network access control

The standard provides an authentication mechanism for devices wishing to attach to a L A N or wireless network

The use of 802.1x can prevent rogue access points and other unauthorized devices from becoming insecure backdoors

Copyright © 2016, 2012, 2009 by Pearson Education, Inc.

All Rights Reserved

Medical Law and Ethics, Fifth Edition

Bonnie F. Fremgen

Copyright © 2017 Pearson Education, Inc. All Rights Reserved

The main threat involving wireless access

points is unauthorized access to the network. The principal approach for preventing

such access is the IEEE 802.1X standard for port-based network access control. The

standard provides an authentication mechanism for devices wishing to attach to a

LAN or wireless network. The use of 802.1X can prevent rogue access points and

other unauthorized devices from becoming insecure backdoors.

Section 5.3 provides an introduction to 802.1X.

11

Securing Wireless Networks

Use encryption

Use antivirus, antispyware software and a firewall

Turn off identifier broadcasting

Change the identifier on your router from the default

Change your router’s pre-set password for administration

Allow only specific computers to access your wireless network

Copyright © 2016, 2012, 2009 by Pearson Education, Inc.

All Rights Reserved

Medical Law and Ethics, Fifth Edition

Bonnie F. Fremgen

Copyright © 2017 Pearson Education, Inc. All Rights Reserved

[CHOI08] recommends the following techniques for

wireless network security:

1. Use encryption. Wireless routers are typically equipped with built-in encryption

mechanisms for router-to-router traffic.

2. Use antivirus and antispyware software, and a firewall. These facilities should

be enabled on all wireless network endpoints.

3. Turn off identifier broadcasting. Wireless routers are typically configured to

broadcast an identifying signal so that any device within range can learn of the

router’s existence. If a network is configured so that authorized devices know

the identity of routers, this capability can be disabled, so as to thwart attackers.

4. Change the identifier on your router from the default. Again, this measure

thwarts attackers who will attempt to gain access to a wireless network using

default router identifiers.

5. Change your router’s pre-set password for administration. This is another prudent

step.

6. Allow only specific computers to access your wireless network. A router can

be configured to only communicate with approved MAC addresses. Of course,

MAC addresses can be spoofed, so this is just one element of a security strategy.

12

Mobile Device Security

Mobile devices have become an essential element for organizations as part of the overall network infrastructure

Prior to the widespread use of smartphones, network security was based upon clearly defined perimeters that separated trusted internal networks from the untrusted Internet

Due to massive changes, an organization’s networks must now accommodate:

Growing use of new devices

Cloud-based applications

De-perimeterization

External business requirements

Copyright © 2016, 2012, 2009 by Pearson Education, Inc.

All Rights Reserved

Medical Law and Ethics, Fifth Edition

Bonnie F. Fremgen

Copyright © 2017 Pearson Education, Inc. All Rights Reserved

Prior to the widespread use of smartphones, the dominant paradigm for computer

and network security in organizations was as follows. Corporate IT was tightly controlled.

User devices were typically limited to Windows PCs. Business applications

were controlled by IT and either run locally on endpoints or on physical servers

in data centers. Network security was based upon clearly defined perimeters that

separated trusted internal networks from the untrusted Internet. Today, there have

been massive changes in each of these assumptions. An organization’s networks

must accommodate the following:

• Growing use of new devices: Organizations are experiencing significant growth

in employee use of mobile devices. In many cases, employees are allowed to

use a combination of endpoint devices as part of their day-to-day activities.

• Cloud-based applications: Applications no longer run solely on physical

servers in corporate data centers. Quite the opposite, applications can run

anywhere—on traditional physical servers, on mobile virtual servers, or in the

cloud. Additionally, end users can now take advantage of a wide variety of

cloud-based applications and IT services for personal and professional use.

Facebook can be used for an employee’s personal profiles or as a component

of a corporate marketing campaign. Employees depend upon Skype to speak

with friends abroad or for legitimate business video conferencing. Dropbox

and Box can be used to distribute documents between corporate and personal

devices for mobility and user productivity.

• De-perimeterization: Given new device proliferation, application mobility,

and cloud-based consumer and corporate services, the notion of a static network

perimeter is all but gone. Now there are a multitude of network perimeters

around devices, applications, users, and data. These perimeters have also

become quite dynamic as they must adapt to various environmental conditions

such as user role, device type, server virtualization mobility, network location,

and time-of-day.

• External business requirements: The enterprise must also provide guests,

third-party contractors, and business partners network access using various

devices from a multitude of locations.

The central element in all of these changes is the mobile computing device.

Mobile devices have become an essential element for organizations as part of the

overall network infrastructure. Mobile devices such as smartphones, tablets, and

memory sticks provide increased convenience for individuals as well as the potential

for increased productivity in the workplace. Because of their widespread use and

unique characteristics, security for mobile devices is a pressing and complex issue.

In essence, an organization needs to implement a security policy through a combination

of security features built into the mobile devices and additional security controls

provided by network components that regulate the use of the mobile devices.

13

Security Threats (1 of 3)

Major security concerns for mobile devices:

Lack of physical security controls

The security policy for mobile devices must be based on the assumption that any mobile device may be stolen or at least accessed by a malicious party

Use of untrusted mobile devices

The organization must assume that not all devices are trustworthy

Copyright © 2016, 2012, 2009 by Pearson Education, Inc.

All Rights Reserved

Medical Law and Ethics, Fifth Edition

Bonnie F. Fremgen

Copyright © 2017 Pearson Education, Inc. All Rights Reserved

Mobile devices need additional, specialized protection measures beyond those

implemented for other client devices, such as desktop and laptop devices that are

used only within the organization’s facilities and on the organization’s networks.

SP 800-14 (Guidelines for Managing and Securing Mobile Devices in the Enterprise ,

July 2012) lists seven major security concerns for mobile devices. We …