Wireless Engineering Body of Knowledge (WEBOK) Wireless Security

1. Wireless Engineering Body of Knowledge (WEBOK)Wireless Security WEBOK Tutorial Paul Kubik

2. What is Wireless Security? • Confidentiality: the communication data are only disclosed to authorized users. • Integrity: the data in the communication retain their veracity and are not able to be modified by unauthorized users. • Availability: authorized users are granted timely access and sufficient bandwidth to access the data.

3. What is Wireless Security? • Why is Wireless Security important? • Fraud, Theft – Stealing customer login details from a WiFi hotspot • Sabotage – Disabling a local 2G cellular network using a jamming device • Espionage – Stealing a phonebook from a mobile phone via bluetooth • Malicious – Distribution of Mobile viruses, unsolicited Bluetooth advertising etc. • How can we protect technology through Security? • Encryption – protects the information stored in a message • Authentication – validates the identity of end-points in a communication • Authorization - restricts access to a service through the use of authentication systems. • Certification – authentication of end-points by a third party

4. What is Wireless Security? • What type of attacks are there?

5. What is Wireless Security? Common concepts in security • Private Key - two (or more) parties share the same key, and that key is used to encrypt data from clear-text to a cipher-text. Private key cryptography relies on keeping the key secret • Eg. AES, DES, 3-DES • Public Key – each party has a pair of keys. One key is public and the other is private. A message encrypted with the public key can be decrypted with the private key. The public key can be made known to all parties (including attackers). The private key is kept secret. • Eg. RSA, Diffie-Hellman

6. Network Access Control • Network Access Control is used to authenticate, authorize and account for a user or client on the network • Challenge-Response Authentication • The authenticating party asks for information that could only be known to the user • Network Access Control protocols: • RADIUS • Diameter • Extensible Access Protocol

7. Network Access Control – RADIUS • User authenticates with NAS using a username/password • NAS sends Access-request to RADIUS server • RADIUS server generates an Access-Challenge for the user. • User calculates hash and sends response to the RADIUS server • User is authenticated as an end-point in the network (Access-Accept)

8. Network Access Control – Diameter • Failover: supports application-layer acknowledgment and defines failover algorithms. • Confidentiality: IPSEC support is mandatory for Diameter and TLS is optional. • Reliable transport: Transmission Control Protocol (TCP) or STCP protocols. • Server-initiated messages: Mandatory support allowing re-authentication/re-authorization • Auditability: Data-object security mechanisms preventing against untrusted proxies modifying attributes or packet headers • Capability negotiation: Error messages, capability negotiation, mandatory/non-mandatory flags for attributes (AVPs). • Peer discovery and configuration: Dynamic discovery of peers using Domain Name System (DNS). Dynamic session keys via transmission-level security. • Roaming support: Supports user roaming, interdomain exchange of user and accounting information.

9. Network Access Control - EAP • Extensible Access Protocol is a authentication framework, not a specific implementation. It defines methods and common functions used for authentication. • Supplicant – The party that wants to be authenticated • Authenticator - The party that demands proof of authentication • Four types of messages are defined in EAP: request, response, success, and failure. • The authenticator sends a request message to the supplicant asking for a response message to authenticate. If the authentication is successful, a success message is sent to the supplicant; if not, a failure message is sent. • Encapsulation on IEEE wireless LANs, IEEE-802.11i • WPA, WPA2 Standard • EAP-TLS, EAP-TTLS, PEAP

10. Network Access Control – 802.1x • An authentication protocol based on EAP • The supplicant is the authenticating user, sends an EAP-Start message to the authenticator • The authenticator is the Wireless Access Point (802.11), sends an EAP-Request Identity to the supplicant • The authenticator only allows the supplicant to generate EAP traffic (EAPoL) until it has been authenticated • The authentication server determines whether a supplicant is authenticated (eg RADIUS server)

11. NAC Example (1) • The Traffic Capture is RADIUS conversation using EAP-TLS • Supplicant MAC: Z-Com_64:61:dc • Authenticator MAC: 3com_7a:eb:fc IP Addr: 192.168.4.62 • Auth Server IP Addr: 192.168.4.51 • 3: The supplicant sends an EAP Response containing “mobile@lab” • 4: The authenticator sends a RADIUS packet to the authentication server containing the connection details https://www.openpacket.org/

12. NAC Example (2) • 8: The authentication server sends an access-challenge to verify the supplicant’s identity. • 10: The authenticator requests that the supplicant use EAP-TLS to verify the user identity • 26: The authentication server decides that client certificate is valid and the supplicant is a known user • 29: Now the authenticator must still make sure that the supplicant has the correct WPA pre-shared key

13. Wireless LAN Security • Service Set Identifier (SSID) - wireless LAN name used client to identify the network • Media Access Control (MAC) address -administrator may specify which MACs are allowed to access the network • Security Algorithm – used for network authentication, including WEP, WPA or WPA2

14. WLAN Security - WEP WEP • Initialization Vector (IV) – 24-bit seed value to initialize the cryptographic system • Stream cipher (RC4) – 40-bit, 104-bit keys. Generates a key which is XOR’ed with the message. A different sequence is used for each message • Integrity checking (CRC-32) – computed and encrypted on each message, becomes the Integrity Check Value (ICV) on the frame

15. WLAN Security - TKIP • TKIP is used to enhance the RC4 cipher. It is designed to strengthen the WEP protocol (based on RC4) without significant performance degradation • Message encryption using the RC4 algorithm • Integrity protection, using the Message Integrity Code (MIC) • Replay prevention, using a frame sequencing technique; and • Use of a new encryption key for each frame.

16. WLAN Security - CCMP • CCMP is used to enhance the AES cipher. AES is the secure cipher used by WPA/WPA2 • CCMP provides authentication and privacy features based on AES • Integrity control (MIC) • Message encryption (payload only) • CCMP is designed for a 128-bit key and block size

17. WLAN Security – WPA/WPA2 WPA • RC4 Cipher. TKIP/MIC Encryption • Implements partial 802.11i standard • TKIP generates a sequence of WEP keys based on a master key. • Message Integrity Code (MIC) and ICV (Integrity Check Value) identify if the packet is tampered with WPA2 • AES Cipher (instead of RC4). AES-CCMP Encryption • Implements full 802.11i standard, known as RSN • AES is a secure cipher that can be implemented in hardware. • CCMP arranges for Message Integrity Control (MIC) and Message encryption (payload only)

18. WLAN Security Example • Securing your network • Enable WPA/WPA2 security on the access point. • Change the default admin password • Change the default SSID and disable broadcast. • Disable DHCP, enable MAC address filtering

19. Cellular Security AMPS Security • Analog FM system. Unencrypted channels • ESN / MIN used for Customer and Handset registration on the network CDMA Security • Subscriber Authentication (CAVE) • Subscriber Identity confidentiality (TMSI). No SIM card • Spreading sequences on physical channel GSM Security • Subscriber Authentication (A3/COMP128) • Subscriber Identity confidentiality (TMSI). Removable SIM card • Encryption of Air interface only UMTS security • Mutual authentication (Subscriber and Network) • Encryption from Air interface to RNC • Mechanism for upgrading security features.

20. Cellular Security – CDMA

21. Cellular Security – GSM • IMEI (International Mobile Equipment Identity) is a unique 17 or 15 digit code used to identify a Mobile Station (hardware) • IMSI (International Mobile Subscriber Identity) is a unique 15-digit code used to identify a subscriber (user) • Ki (128-bit) is a secret key shared between the Mobile Station and the HLR • Kc (64-bit) is a Session Key for channel encryption. Kc is generated by the Mobile Station from RAND and Ki using the A8 algorithm. • RAND (128-bit) is a random challenge generated by the HLR. • SRES (32-bit) is a Signed Response generated by both the Mobile Station and the HLR from the RAND to verify identity • HLR / AuC – Stores the IMSI and Ki for Mobile Stations • EIR – Stores an IMEI black-list to prevent calls from stolen or unauthorized Mobile Stations.

22. Cellular Security – GSM • The Mobile Station (MS) signs into the network. • The HLR uses the A8 algorithm to generate RAND, SRES and Kc • The HLR sends RAND to the RNC and the MS • The MS generates SRES from RAND and Ki using the A3 algorithm • The MS sends SRES to the MSC • The MSC verifies SRES (Mobile) and SRES (HLR) • The MS generates Kc from RAND and Ki using the A8 algorithm • The BTS verifies Kc (MS) and Kc (HLR) • The MS initialises the A5 algorithm with Kc and the frame number • An encrypted channel between the MS and the BTS is established HLR BTS Mobile Station MSC RAND Ki, Kc Ki, Kc SRES

23. Bluetooth Security Bluetooth Security Attacks • Bluejacking - attempt to send a phone contact or business card to another nearby phone for the purpose of spamming information / advertising • Bluesnarfing - stealing data (messages, calendar, phone book etc) from the target device in an unauthorised manner which includes bypassing the usual paring requirement. • Bluebugging - victim device is controlled by the attacker who sends commands to perform actions as if having physical access to the device Security attributes • Bluetooth address : unique device identifier (48-bit). The first 3 bytes are assigned to a manufacturer. The last 3 bytes allocated by the manufacturer. • "Discoverable" mode : determines whether the device is visible to other devices. • PIN Code : Four digit secret code entered into both devices to establish a Link Key (128-bit) • Frequency hopping : Pseudo-random sequence (1600 hops / second)

24. Wireless Security END