Fundamentals of Radio Frequency Communications and Wireless Security

1. Basic radio frequency communications - 2 Session 1

2. Contents • Basic security concepts • Attacks against wireless networks • Wireless technologies • Classification according to the range

3. Basic security concepts • Vulnerability • An inherent weakness in the design, configuration, implementation of a network or system • This can take any form and can be intentional, accidental, or simply an act of nature • Threat • Any possible event that can disrupt the operation, functioning, integrity, or availability of a network or system

4. Basic security concepts • Attack • A specific technique used to exploit a vulnerability • Example • A threat could be a denial of service • A vulnerability is in the design of a communication system • An attack could be jamming

5. Basic security concepts • Confidentiality • Providing confidentiality means hiding the information from an unauthorized third party • Integrity • Ensuring data integrity means protecting data from being modified without authorization • Availability • The wireless network should be always available to be used

6. Basic security concepts • Privacy • Ensuring privacy means hiding the user identity, location or service usage • Authentication • Process that ensures that only legitimate users (possessing certain credentials) can access the wireless network

7. Basic security concepts • Access Control • Process that grants a legitimate user access to certain information that he/she is allowed to access • Non-repudiation • Activities that prevent users from denying the use of wireless networks

8. Attacks against wireless networks • Passive attacks (1) • Channel eavesdropping • An attacker can place an antenna to hear the information between the victim transmitter and receiver • Channel overuse • The radio spectrum is a shared resource • A wireless operator or a user may make an excessive use of the radio spectrum and prevent others from accessing it

9. Attacks against wireless networks • Passive attacks (2) • Traffic analysis • An analysis that shows characteristics of the traffic, e.g. how frequently the communication takes place • Active attacks (1) • Channel jamming • Part of denial of service attacks • Performed by transmitting at the same time in the same communication channel as the victim

10. Attacks against wireless networks • Active attacks (2) • Identity cheat • An attacker impersonates a legitimate user in the wireless networks • Spoofing • An attacker retrieves data and sends other data to the victim user • Data alteration • An attacker modifies the content of the information

11. Attacks against wireless networks

12. Attacks against wireless networks • Specific vulnerabilities of wireless networks regarding mobility, i.e. the fact that a device can roam across different wireless networks and network operators (1) • Privacy of a user is threatened • Mobile device is small • Limited storage, computing power and energy • Strong protection measures (e.g. strong cryptography) are difficult to implement

13. Attacks against wireless networks • Specific vulnerabilities of wireless networks regarding mobility, i.e. the fact that a device can roam across different wireless networks and network operators (2) • Mobile device can be easily stolen • This may lead to misuse and reverse engineering

14. Wireless technologies • RFID • Personal networks • Bluetooth (IEEE 802.15.1) • ZigBee (IEEE 802.15.4) • Wireless LAN (IEEE 802.11) • Cellular networks • GSM • UMTS (3G)

15. Wireless technologies • Wireless mesh networks • Mobile ad hoc networks • Hybrid ad hoc networks • Vehicular networks • Sensor networks • Integrated networks

16. RFID • RFID (Radio Frequency Identification) • Serves for automatic and secure reading of an ID-number • There are also RFID devices capable of storing data – wireless memory (e.g. electronic passports) • Applications (http://www1.nrk.no/nett-tv/klipp/164552) • Logistics • Ticketing • Transport (e.g. Autopass), etc.

17. RFID • Operation • An RFID tag is mounted on the object to be identified • The tag consists of a chip and an antenna • Energy needed for operation of the tag is (usually) received from the reader – a radio transmitter • When the tag finds itself in the field of the reader’s radio signal, it transmits an echo • The echo is checked in the reader’s database and thus the object is identified.

18. Personal networks • Bluetooth • A short-range communications system intended to replace the cables connecting portable and/or fixed electronic devices. • The system offers services that enable the connection of devices and the exchange of data between these devices.

19. Personal networks • Bluetooth

20. Personal networks • ZigBee • A short-range communication system intended to facilitate communication between various technical devices, tipically home appliances. • Simpler messages than Bluetooth • More scalable than Bluetooth

21. Wireless LAN • Wireless LAN enables connectivity of computing devices (PCs, laptop, printers, etc.) by means of a radio link • Such a connection is transparent for the users • There is no logical difference between a wired and a wireless connection.

22. Wireless LAN

23. Cellular networks • Cellular network • A radio network made up of a number of radio cells, each served by a fixed transmitter, known as a base station. • These cells are used to cover different areas in order to provide radio coverage over a wider area than the area of one cell • Example • Mobile telephony networks (GPS, UMTS)

24. Cellular networks

25. Cellular networks • Abbreviations (1) • SIM – Subscriber Identity Module • MS – Mobile Station • USIM – Universal Subscriber Identity Module • ME – Mobile Equipment • TE – Terminal Equipment • UE – User Equipment • BTS – Base Transceiver Station • BSC – Base Station Controller

26. Cellular networks • Abbreviations (2) • Node B – Analogue to BTS in UMTS • RNC – Radio Network Controller • BSS – Base Station Subsystem • RNS – Radio Network Subsystem • MSC – Mobile Switching Center • GMSC – Gateway MSC • SGSN – Serving GPRS Support Node • GGSN – Gateway GPRS Support Node

27. Cellular networks • Abbreviations (3) • VLR – Visitor Location Register • HLR – Home Location Register • EIR – Equipment Identity Register • AuC – Authentication Center • PSTN – Public Switched Telephone Network • PLMN – Public Land Mobile Network

28. Wireless mesh networks • Mesh network • Data communication through fixed nodes • The connectivity allows continued communication even if some of the nodes in the network stop functioning • Wireless mesh network • Communication between the nodes is wireless • Similar to mobile ad hoc networks, but the nodes are in general not mobile.

29. Mobile ad hoc networks (MANETs) • A self-configuring network of mobile routers (and associated hosts) connected by wireless links • Together, they form an arbitrary topology • The routers are free to move randomly and organize themselves arbitrarily

30. Mobile ad hoc networks (MANETs) • The network's wireless topology may change rapidly and unpredictably • Such a network may operate in a standalone fashion, or may be connected to a larger Internet

31. Mobile ad hoc networks (MANETs)

32. Hybrid ad hoc networks • A structure-based network that is extended using multi-hop communications • The existence of a communication link between the mobile station and the base station is not required • A mobile station that has no direct connection with a base station can use other mobile stations as relays.

33. Hybrid ad hoc networks

34. Vehicular networks (VANETs) • A form of MANET • Intended to provide communication among nearby vehicles and between vehicles and nearby fixed equipment (roadside equipment) • The main goal • providing safety and comfort for passengers

35. Vehicular networks (VANETs) • A special electronic device is placed inside each vehicle • Provides ad hoc network connectivity for the passengers • This network tends to operate without any infrastructure

36. Vehicular networks (VANETs)

37. Wireless sensor networks • Spatially distributed autonomous devices • Use sensors to cooperatively monitor physical or environmental conditions (temperature, sound, vibration, pressure, motion, pollutants, etc.) at different locations. • In addition to one or more sensors, each node in a sensor network is equipped with a radio transceiver, a small microcontroller, and an energy source, usually a battery.

38. Wireless sensor networks

39. Integrated networks • Modern networks often integrate many types of networks, including various types of wireless networks • Example • Sensor networks and ad hoc networks are often integrated to make a single network

40. Integrated networks

41. Classification according to range • According to the range, wireless networks are classified in the following way • Short-range • Bluetooth, ZigBee • Medium-range • WLAN • Medium long-range • Cellular • Long-range • Satellite global area networks

42. Classification according to range