Home > Articles > Networking > Wireless/High Speed/Optical

This chapter is from the book

Understanding WLAN Security

As discussed previously, the most tangible benefit of wireless is cost reduction. In addition to increasing productivity, WLANs increase work quality. However, a security breach resulting from a single unsecured access point can negate hours spent securing the corporate network and even ruin an organization. You must understand the security risks of WLANs and how to reduce those risks.

After completing this section, you will be able to describe WLAN security issues and the features available to increase WLAN security.

Wireless LAN Security Threats

With the lower costs of IEEE 802.11b/g systems, it is inevitable that hackers have many more unsecured WLANs from which to choose. Incidents have been reported of people using numerous open source applications to collect and exploit vulnerabilities in the IEEE 802.11 standard security mechanism, Wired Equivalent Privacy (WEP). Wireless sniffers enable network engineers to passively capture data packets so that they can be examined to correct system problems. These same sniffers can be used by hackers to exploit known security weaknesses. Figure 3-4 shows the most common threats to wireless networks.

Figure 3-4

Figure 3-4 Wireless LAN Threats

"War driving" originally meant using a cellular scanning device to find cell phone numbers to exploit. War driving now also means driving around with a laptop and an 802.11b/g client card to find an 802.11b/g system to exploit.

Most wireless devices sold today are WLAN-ready. End users often do not change default settings, or they implement only standard WEP security, which is not optimal for securing wireless networks. With basic WEP encryption enabled (or, obviously, with no encryption enabled), collecting data and obtaining sensitive network information, such as user login information, account numbers, and personal records, is possible.

A rogue access point (AP) is an AP placed on a WLAN and used to interfere with normal network operations, for example, with denial of service (DoS) attacks. If a rogue AP is programmed with the correct WEP key, client data could be captured. A rogue AP also could be configured to provide unauthorized users with information such as MAC addresses of clients (both wireless and wired), to capture and spoof data packets, or, at worst, to gain access to servers and files. A simple and common version of a rogue AP is one installed by employees with authorization. Employees install access points intended for home use without the necessary security configuration on the enterprise network, causing a security risk for the network.

Mitigating Security Threats

To secure a WLAN, the following components are required:

  • Authentication: To ensure that legitimate clients and users access the network via trusted access points
  • Encryption: To provide privacy and confidentiality
  • Intrusion Detection Systems (IDS) and Intrusion Protection Systems (IPS): To protect from security risks and availability

The fundamental solution for wireless security is authentication and encryption to protect the wireless data transmission. These two wireless security solutions can be implemented in degrees; however, both apply to small office/home office (SOHO) and large enterprise wireless networks. Larger enterprise networks need the additional levels of security offered by an IPS monitor. Current IPS systems do not only detect wireless network attacks, but also provide basic protection against unauthorized clients and access points. Many enterprise networks use IPS for protection not primarily against outside threats, but mainly against unintentional unsecured access points installed by employees desiring the mobility and benefits of wireless.

Evolution of Wireless LAN Security

Almost as soon as the first WLAN standards were established, hackers began trying to exploit weaknesses. To counter this threat, WLAN standards evolved to provide more security. Figure 3-5 shows the evolution of WLAN security.

Figure 3-5

Figure 3-5 Evolution of Wireless LAN Security

Initially, 802.11 security defined only 64-bit static WEP keys for both encryption and authentication. The 64-bit key contained the actual 40-bit key plus a 24-bit initialization vector. The authentication method was not strong, and the keys were eventually compromised. Because the keys were administered statically, this method of security was not scalable to large enterprise environments. Companies tried to counteract this weakness with techniques such as Service Set Identifier (SSID) and MAC address filtering.

The SSID is a network-naming scheme and configurable parameter that both the client and the AP must share. If the access point is configured to broadcast its SSID, the client associates with the access point using the SSID advertised by the access point. An access point can be configured to not broadcast the SSID (SSID cloaking) to provide a first level of security. The belief is that if the access point does not advertise itself, it is harder for hackers to find it. To allow the client to learn the access point SSID, 802.11 allows wireless clients to use a null string (no value entered in the SSID field), thereby requesting that the access point broadcast its SSID. However, this technique renders the security effort ineffective because hackers need only send a null string until they find an access point.

Access points also support filtering using a MAC address. Tables are manually constructed on the AP to allow or disallow clients based upon their physical hardware address. However, MAC addresses are easily spoofed, and MAC address filtering is not considered a security feature.

While 802.11 committees began the process of upgrading WLAN security, enterprise customers needed wireless security immediately to enable deployment. Driven by customer demand, Cisco introduced early proprietary enhancements to RC4-based WEP encryption. Cisco implemented Temporal Key Integrity Protocol (TKIP) per-packet keying or hashing and Cisco Message Integrity Check (Cisco MIC) to protect WEP keys. Cisco also adapted 802.1x wired authentication protocols to wireless and dynamic keys using Cisco Lightweight Extensible Authentication Protocol (Cisco LEAP) to a centralized database.

Soon after the Cisco wireless security implementation, the Wi-Fi Alliance introduced WPA as an interim solution that was a subset of the expected IEEE 802.11i security standard for WLANs using 802.1x authentication and improvements to WEP encryption. The newer key-hashing TKIP versus Cisco Key Integrity Protocol and message integrity check (MIC versus Cisco MIC) had similar features but were not compatible.

Today, 802.11i has been ratified, and Advanced Encryption Standard (AES) has replaced WEP as the latest and most secure method of encrypting data. Wireless Intrusion Detection Systems are available to identify and protect the WLAN from attacks. The Wi-Fi Alliance certifies 802.11i devices under WPA2.

Wireless Client Association

In the client association process, access points send out beacons announcing one or more SSIDs, data rates, and other information. The client sends out a probe and scans all the channels and listens for beacons and responses to the probes from the access points. The client associates to the access point that has the strongest signal. If the signal becomes low, the client repeats the scan to associate with another access point (this process is called roaming). During association, the SSID, MAC address, and security settings are sent from the client to the access point and checked by the access point. Figure 3-6 illustrates the client association process.

Figure 3-6

Figure 3-6 Client Association

A wireless client's association to a selected access point is actually the second step in a two-step process. First, authentication and then association must occur before an 802.11 client can pass traffic through the access point to another host on the network. Client authentication in this initial process is not the same as network authentication (entering username and password to get access to the network). Client authentication is simply the first step (followed by association) between the wireless client and access point, and it establishes communication. The 802.11 standard specifies only two different methods of authentication: open authentication and shared key authentication. Open authentication is simply the exchange of four "hello" type packets with no client or access point verification, to allow ease of connectivity. Shared key authentication uses a statically defined WEP key, known between the client and access point, for verification. This same key might or might not be used to encrypt the actual data passing between a wireless client and an access point based on user configuration.

How 802.1x Works on WLANs

The access point, acting as the authenticator at the enterprise edge, allows the client to associate using open authentication. The access point then encapsulates any 802.1x traffic bound for the authentication server and sends it to the server. All other network traffic is blocked, meaning that all other attempts to access network resources are blocked. Figure 3-7 shows how 802.1x functions on a wireless network.

Figure 3-7

Figure 3-7 802.1x Authentication

Upon receiving RADIUS traffic bound for the client, the access point encapsulates it and sends the information to the client. Although the server authenticates the client as a valid network user, this process allows the client to validate the server as well, ensuring that the client is not logging into a phony server.

While an enterprise network uses a centralized authentication server, smaller offices or business might simply use the access point with preshared keys as the authentication server for wireless clients.

WPA and WPA2 Modes

WPA provides authentication support via 802.1x and a preshared key (PSK); 802.1x is recommended for enterprise deployments. WPA provides encryption support via TKIP. TKIP includes MIC and per-packet keying (PPK) via initialization vector hashing and broadcast key rotation.

In comparison to WPA, WPA2 authentication is not changed, but the encryption used is AES-Counter with CBC MAC Protocol (AES-CCMP). Table 3-2 compares the two WPA modes.

Table 3-2. WPA Modes

WPA

WPA2

Enterprise Mode (Business, Education, Government)

Authentication: IEEE 802.1x/EAP

Encryption: TKIP/MIC

Authentication: IEEE 802.1x/EAP

Encryption: AES-CCMP

Personal Mode (SOHO, Home/Personal)

Authentication: PSK

Encryption: TKIP/MIC

Authentication: PSK

Encryption: AES-CCMP

Enterprise Mode

Enterprise Mode is a term given to products that are tested to be interoperable in both PSK and 802.1x/Extensible Authentication Protocol (EAP) modes of operation for authentication. When 802.1x is used, an authentication, authorization, and accounting (AAA) server (the Remote Authentication Dial-In User Service (RADIUS) protocol for authentication and key management and centralized management of user credentials) is required. Enterprise Mode is targeted to enterprise environments.

Personal Mode

Personal Mode is a term given to products tested to be interoperable in the PSK-only mode of operation for authentication. It requires manual configuration of a preshared key on the AP and clients. PSK authenticates users via a password, or identifying code, on both the client station and the AP. No authentication server is needed. Personal Mode is targeted to SOHO environments.

Summary of Understanding WLAN Security

The following summarizes the key points that were discussed in this lesson:

  • With 802.1x, the access point, acting as the authenticator at the enterprise edge, allows the client to associate using open authentication.
  • WPA provides authentication support via IEEE 802.1x and PSK.
    • Enterprise Mode is a term given to products that are tested to be interoperable in both PSK and IEEE 802.1x/EAP modes of operation for authentication.
    • Personal Mode is a term given to products tested to be interoperable in the PSK-only mode of operation for authentication.

InformIT Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from InformIT and its family of brands. I can unsubscribe at any time.

Overview


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about products and services that can be purchased through this site.

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

Collection and Use of Information


To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.

Surveys

Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites, develop new products and services, conduct educational research and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.

Newsletters

If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email information@informit.com.

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information


Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.

Security


Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.

Children


This site is not directed to children under the age of 13.

Marketing


Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information


If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.

Choice/Opt-out


Users can always make an informed choice as to whether they should proceed with certain services offered by InformIT. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.informit.com/u.aspx.

Sale of Personal Information


Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents


California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure


Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.

Links


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact


Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice


We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020