1. Wireless and Instant Messaging
Chapter 8

2. Learning Objectives
Understand security issues related to wireless data transfer
Understand the x standards
Understand Wireless Application Protocol (WAP) and how it works
Understand Wireless Transport Layer Security (WTLS) protocol and how it works
continued…

3. Learning Objectives
Understand Wired Equivalent Privacy (WEP) and how it works
Conduct a wireless site survey
Understand instant messaging

4. 802.11
IEEE group responsible for defining interface between wireless clients and their network access points in wireless LANs
First standard finalized in 1997 defined three types of transmission at Physical layer
Diffused infrared - based on infrared transmissions
Direct sequence spread spectrum (DSSS) - radio-based
Frequency hopping spread spectrum (FHSS) - radio-based
continued…

5. 802.11 Established WEP as optional security protocol
Specified use of 2.4 GHz industrial, scientific, and medical (ISM) radio band
Mandated 1 Mbps data transfer rate and optional 2 Mbps data transfer rate
Most prominent working groups: b, a, i, and g

6. 802.11a “High-Speed Physical Layer in the 5 GHz Band”
Sets specifications for wireless data transmission of up to 54 Mbps in the 5 GHz band
Uses an orthogonal frequency division multiplexing encoding scheme rather than FHSS or DSSS
Approved in 1999

7. 802.11b “Higher-Speed Layer Extension in the 2.4 GHz Band”
Establishes specifications for data transmission that provides 11 Mbps transmission (with fallback to 5.5, 2, and 1 Mbps) at 2.4 GHz band
Sometimes referred to as “Wi-Fi” when associated with WECA certified devices
Uses only DSSS
Approved in 1999

8. 802.11c
Worked to establish MAC bridging functionality for to operate in other countries
Folded into 802.1D standard for MAC bridging

9. 802.11d
Responsible for determining requirements necessary for to operate in other countries
Continuing

10. 802.11e
Responsible for creating a standard that will add multimedia and quality of service (QoS) capabilities to wireless MAC layer and therefore guarantee specified data transmission rates and error percentages
Proposal in draft form

11. 802.11f
Responsible for creating a standard that will allow for better roaming between multivendor access points and distribution systems
Ongoing

12. 802.11g
Responsible for providing raw data throughput over wireless networks at a throughput rate of 22 Mbps or more
Draft created in January 2002; final approval expected in late 2002 or early 2003

13. 802.11h
Responsible for providing a way to allow for European implementation requests regarding the 5 GHz band
Requirements
Limits PC card from emitting more radio signal than needed
Allows devices to listen to radio wave activity before picking a channel on which to broadcast
Ongoing; not yet approved

14. 802.11i Responsible for fixing security flaws in WEP and 802.1x
Hopes to eliminate WEP altogether and replace it with Temporal Key Integrity Protocol (TKIP), which would require replacement of keys within a certain amount of time
Ongoing; not yet approved

15. 802.11j
Worked to create a global standard in the 5 GHz band by making high-performance LAN (HiperLAN) and a interoperable
Disbanded after efforts in this area were mostly successful

17. Wireless Application Protocol (WAP)
Open, global specification created by the WAP Forum
Designed to deliver information and services to users of handheld digital devices
Compatible with most wireless networks
Can be built on any operating system

18. WAP-Enabled Devices

19. WAP-Enabled Devices

20. How WAP 1x Works WAP 1.x Stack
Set of protocols created by the WAP Forum that alters the OSI model
Five layers lie within the top four (of seven) layers of the OSI model
Leaner than the OSI model
Each WAP protocol makes data transactions as compressed as possible and allows for more dropped packets than OSI model

21. WAP 1.x Stack Compared to OSI/Web Stack

22. Differences Between Wireless and Wired Data Transfer
WAP 1.x stack protocols require that data communications between clients (wireless devices) and servers pass through a WAP gateway
Network architectural structures

23. WAP versus Wired Network

24. The WAP 2.0 Stack
Eliminates use of WTLS; relies on a lighter version of TLS – the same protocol used on the common Internet stack – which allows end-to-end security and avoids any WAP gaps
Replaces all other layers of WAP 1.x by standard Internet layers
Still supports the WAP 1.x stack in order to facilitate legacy devices and systems

26. Additional WAP 2.0 Features
WAP Push
User agent profile
Wireless Telephony Application
Extended Functionality Interface (EFI)
Multimedia Messaging Service (MMS)

27. Wireless Transport Layer Security (WTLS) Protocol
Provides authentication, data encryption, and privacy for WAP 1.x users
Three classes of authentication
Class 1
Anonymous; does not allow either the client or the gateway to authenticate each other
Class 2
Only allows the client to authenticate the gateway
Class 3
Allows both the client and the gateway to authenticate each other

28. WTLS Protocol: Steps of Class 2 Authentication
WAP device sends request for authentication
Gateway responds, then sends a copy of its certificate – which contains gateway’s public key – to the WAP device
WAP device receives the certificate and public key and generates a unique random value
WAP gateway receives encrypted value and uses its own private key to decrypt it

29. WTLS Security Concerns
Security threats posed by WAP gap
Unsafe use of service set identifiers (SSIDs)

30. Wired Equivalent Privacy (WEP)
Optional security protocol for wireless local area networks defined in the b standard
Designed to provide same level of security as a wired LAN
Not considered adequate security without also implementing a separate authentication process and providing for external key management

31. Wireless LAN (WLAN)
Connects clients to network resources using radio signals to pass data through the ether
Employs wireless access points (AP)
Connected to the wired LAN
Act as radio broadcast stations that transmit data to clients equipped with wireless network interface cards (NICs)

32. How a WLAN Works

33. APs

34. NICs

35. How WEP Works
Uses a symmetric key (shared key) to authenticate wireless devices (not wireless device users) and to guarantee integrity of data by encrypting transmissions
Each of the APs and clients need to share the same key
Client sends a request to the AP asking for permission to access the wired network
continued…

36. How WEP Works
If WEP has not been enabled (default), the AP allows the request to pass
If WEP has been enabled, client begins a challenge-and-response authentication process

37. WEP’s Weaknesses
Problems related to the initialization vector (IV) that it uses to encrypt data and ensure its integrity
Can be picked up by hackers
Is reused on a regular basis
Problems with how it handles keys

38. Other WLAN Security Loopholes
War driving
Unauthorized users can attach themselves to WLANs and use their resources, set up their own access points and jam the network
WEP authenticates clients, not users
Wireless network administrators and users must be educated about inherent insecurity of wireless systems and the need for care

39. Conducting a Wireless Site Survey
Conduct a needs assessment of network users
Obtain a copy of the site’s blueprint
Do a walk-through of the site
Identify possible access point locations
Verify access point locations
Document findings

40. Instant Messaging (IM)
AOL Instant Messenger (AIM)
MSN Messenger
Yahoo! Messenger
ICQ
Internet Relay Chat (IRC)

41. Definition of IM Uses a real-time communication model
Allows users to keep track of online status and availability of other users who are also using IM applications
Can be used on both wired and wireless devices
Easy and fast
continued…

42. Definition of IM Operates in two models: Peer-to-peer model
May cause client to expose sensitive information
Peer-to-network model
Risk of network outage and DoS attacks making IM communication unavailable

43. Problems Facing IM Lack of default encryption enables packet sniffing
Social engineering overcomes even encryption

44. Technical Issues Surrounding IM
Files transfers
Application sharing

45. Legal Issues Surrounding IM
Possible threat of litigation or criminal indictment should the wrong message be sent or overheard by the wrong person
Currently immune to most corporate efforts to control it
Must be monitored in real time

46. Blocking IM
Install a firewall to block ports that IM products use; IM will be unavailable to all employees
Limited blocking not currently possible

47. Cellular Phone Simple Messaging Service (SMS)
Messages are typed and sent immediately
Problems
Tracking inappropriate messages
Risk of having messages sniffed

48. Chapter Summary
Efforts of IEEE, specifically x standards, to standardize wireless security
Security issues related to dominant wireless protocols
WAP
Connects mobile telephones, PDAs, pocket computers, and other mobile devices to the Internet
WEP
Used in WLANs
continued…

49. Chapter Summary WTLS protocol
Conducting a site survey in advance of building a WLAN
Security threats related to using (IM)