BLUETOOTH TECHNOLOGY/SECURITY
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Presentation Transcript
Group Members SaadAsghar Syed Ziafat Ali Yaweralvi
Bluetooth • The name ‘Bluetooth’ was named after 10th century Viking king in Denmark Harald Bluetooth who united and controlled Denmark and Norway. • The name was adopted because Bluetooth wireless technology is expected to unify the telecommunications and computing industries
Who Started Bluetooth? • Bluetooth Special Interest Group (SIG) • Founded in Spring 1998 • By Ericsson, Intel, IBM, Nokia, Toshiba; • Now more than 2000 organizations joint the SIG
What Is Bluetooth? ☼ Bluetooth is an open standard for short-range digital radio to interconnect a variety of devices Cell phones, PDA, notebook computers, modems, cordless phones, pagers, laptop computers, printers, cameras by developing a single-chip, low-cost, radio-based wireless network technology
Bluetooth • Simplifying communications between: - devices and the internet - data synchronization • Operates in licensed exempt ISM band at 2.4ghz • Uses frequency hoping spread spectrum • Omni directional, no requiring line of sight • Bluetooth offers data speeds of up to 1 Mbps up to 10 meters (Short range wireless radio technology ) • Unlike IrDA, Bluetooth supports a LAN-like mode where multiple devices can interact with each other. • The key limitations of Bluetooth are security and interference with wireless LANs. • Short range wireless radio technology
Bluetooth • Bluetooth is a PAN Technology • Offers fast and reliable transmission for both voice and data • Can support either one asynchronous data channel with up to three simultaneous synchronous speech channels or one channel that transfers asynchronous data and synchronous speech simultaneously • Support both packet-switching and circuit-switching
Bluetooth • Personal Area Network (PAN) Bluetooth is a standard that will … • Eliminate wires and cables between both stationary and mobile devices • Facilitate both data and voice communications • Offer the possibility of ad hoc networks and deliver synchronicity between personal devices
Bluetooth Topology • Bluetooth-enabled devices can automatically locate each other • Topology is established on a temporary and random basis • Up to eight Bluetooth devices may be networked together in a master-slave relationship to form a Piconet
Cont. • One is master, which controls and setup the network • All devices operate on the same channel and follow the same frequency hopping sequence • Two or more piconet interconnected to form a scatter net • Only one master for each piconet • A device can’t be masters for two piconets • The slave of one piconet can be the master of another piconet
Ad-hoc • is a network connection method which is most often associated with wireless devices. • The connection is established for the duration of one session and requires no base station. • Instead, devices discover others within range to form a network for those computers. • Devices may search for target nodes that are out of range by flooding the network with broadcasts that are forwarded by each node. • Connections are possible over multiple nodes (multihop ad hoc network). • Routing protocols then provide stable connections even if nodes are moving around
A piconet • is an ad-hoc computer network of devices using Bluetooth technology protocols to allow one master device to interconnect with up to seven active slave devices • Up to 255 further slave devices can be inactive, or parked, which the master device can bring into active status at any time.
Our Focus • Bluetooth security
Bluetooth Frequency • Has been set aside by the ISM( industrial ,sientific and medical ) for exclusive use of Bluetooth wireless products • Communicates on the 2.45 GHz frequency
Frequency Selection • FH is used for interference mitigation and media access; • TDD (Test-Driven Development) is used for separation of the transmission directions In 3-slot or 5-slot packets
FH-CDMA (Frequency Hopping - Code Division Multiple Access) • Frequency hopping (FH) is one of two basic modulation techniques used in spread spectrum signal transmission. • It is the repeated switching of frequencies during radio transmission, often to minimize the effectiveness of the unauthorized interception or jamming of telecommunications. • It also is known as frequency- hopping code division multiple access (FH-CDMA). • Bluetooth uses a technique called spread-spectrum frequency hopping.
Avoiding Interference : Hopping • In this technique, a device will use 79 individual, randomly chosen frequencies within a designated range • Transmitters change frequency 1600 times a second
Cont. • Each channel is divided into time slots 625 microseconds long • Packets can be up to five time slots wide • Data in a packet can be up to 2,745 bits in length
Cont. • FH-CDMA to separate piconets within a scatternet • More piconets within a scatter net degrades performance • Possible collision because hopping patterns are not coordinated • At any instant of time, a device can participate only in one piconet • If the device participates as a slave, it just synchronize with the master’s hop sequence
Cont. • The master for a piconet can join another piconet as a slave; in this case, all communication within in the former piconet will be suspended . • When leaving a piconet, a slave notifies the master about its absence for certain amount of time. • Communication between different piconets takes place by devices jumping back and forth between these nets
How Does It Work? • Bluetooth is a standard for tiny, radio frequency chips that can be plugged into your devices • These chips were designed to take all of the information that your wires normally send, and transmit it at a special frequency to something called a receiver Bluetooth chip. • The information is then transmitted to your device
BluetoothChip RF Baseband Controller Link Manager Bluetooth Chip
SPECIFICATIONS • Application Specifications • These specifications include the following • Profiles Cordless Telephony • Serial Port • Headset • Intercom • Dialup Networking • Fax • File Transfer • Service Discovery Application • Generic Access
Wireless Technologies • There are two technologies that have been developed as wireless cable replacements: Infrared (IRDA) and radio (Bluetooth).
Why Not Infrared? • Intended for point to point links • Limited to line of sight • have a narrow angle (30 degree cone), • Low penetration power • Distance covered is low(1 meter approx) • have a throughput of 9600 bps to 4 Mbps • IrDA has proven to be a popular technology with compliant ports currently available in an array of devices including: embedded devices, phones, modems, computers (PCs) and laptops, PDAs, printers, and other computer peripherals
Security of Bluetooth • Security in Bluetooth is provided on the radio paths only • Link authentication and encryption may be provided • True end-to-end security relies on higher layer security solutions on top of Bluetooth • Bluetooth provides three security services • Authentication – identity verification of communicating devices • Confidentiality – against information compromise • Authorization – access right of resources/services • Fast FH together with link radio link power control provide protection from eavesdropping and malicious access • Fast FH makes it harder to lock the frequency • Power control forces the adversary to be in relatively close proximity
Security Modes (Authentication ) • Exchange Business Cards • Needs a secret key • A security manager controls access to services and to devices • Security mode 2 does not provide any security until a channel has been established • Key Generation from PIN • PIN: 1-16 bytes. PINs are fixed and may be permanently stored. Many users use the four digit 0000
Bluetooth Key Generation From PIN • Bluetooth Initialization Procedure (Pairing) • Creation of an initialization key (ki) • Creation of a link key Authentication (ka)
Creation of an Initialization Key • PIN and its length (ki)
Creation of a link key Authentication • Challenge-Response Based • Claimant: intends to prove its identity, to be verified • Verifier: validating the identity of another device • Use challenge-response to verify whether the claimant knows the secret (link key) or not . If fail, the claimant must wait for an interval to try a new attempt. • The waiting time is increased exponentially to defend the “try-and-error” authentication attack • Mutual authentication is supported • Challenge (128-bit) • Response (32-bit) • 48-bit device address
Confidentiality • ACO (Authenticated Cipher Offset) is 96-bit, generated during the authentication procedure • ACO and the link key are never transmitted • Encryption key Kc is generated from the current link key • Kc is 8-bit to 128-bit, negotiable between the master and the slave Master suggests a key size Set the “minimum acceptable” key size parameter to prevent a malicious user from driving the key size down to the minimum of 8 bits • The key stream is different for different packet since slot number is different
Three Encryption Modes for Confidentiality • Encryption Mode 1: -- No encryption is performed on any traffic • Encryption Mode 2: -- Broadcast traffic goes unprotected • while uni cast traffic is protected by the unique key • Encryption Mode 3: -- All traffic is encrypted
Trust Levels, Service Levels(authorization ) • Two trust levels: trusted and untrusted • Trusted devices have full access right • Untrusted devices have restricted service access
Bluetooth Security Architecture • Step 1: User input (initialization or pairing) • Two devices need a common pin (1-16 bytes) • Step 2: Authentication key (128-bit link key) generation • Possibly permanent, generated based on the PIN, device address, random numbers, etc. • Step 3: Encryption key (128 bits, store temporarily) • Step 4: key stream generation for xor-ing the payload
Security cont. • The security of the whole system relies on the PIN which may be too short • Users intend to use 4-digit short PINs, or even a null PIN • Utilized new cryptographic primitives, which have not gone through enough security analysis. (E0,E1,E20,E22) algorithms
E0 algorithm • The E0 algorithm is designed specifically for Bluetooth • E0 has gone many security analysis. When used in Bluetooth mode, the security of E0 is decreased from 128-bit to 84-bit; • when used outside of a Bluetooth system, its effective security is only 39-bit • A Bluetooth device resets the E0 key after every 240 output bits, severely limiting the amount of known key stream that may be available to the cryptanalyst.
Short Key Attacks • we focus on .short key. attacks, that still manage to recover the key despite this limitation. • attacker can guess the content of the registers of the three smaller LFSRs and of the E0 combiner state registers with a probability of 2 to power 93. • This attack requires a total of 128 bits of known plaintext and ciphertext. The reverse engineering and verication takes approximately 27 operations. Making the total complexity of the attack 2to power100.
Long Key Attacks • an attack that recovers the session key in a similar way to what showed, only that assuming much more keystream is available • within a packet and therefore the overall complexity was closer to O(2 to power 93).
Short range was a countermeasure to force the attackers to be in close proximity; • now range extenders can be easily built • Attackers grow since information is more attractive • People use Bluetooth not only for personal information, but also for corporate information
Hacker Tools • Bluesnarfing: • is the theft of information from a wireless device through a Bluetooth connection. • By exploiting a vulnerability in the way Bluetooth is implemented on a mobile phone, an attacker can access information -- such as the user's calendar, contact list and e-mail and text messages -- without leaving any evidence of the attack. • Other devices that use Bluetooth, such as laptop computers, may also be vulnerable, although to a lesser extent, by virtue of their more complex systems. • Operating in invisible mode protects some devices, but others are vulnerable as long as Bluetooth is enabled.
Hacker Tools • Bluejacking • is the sending of unsolicited messages over Bluetooth to Bluetooth-enabled devices such as mobile phones, PDAs or laptop computers, sending a vCard which typically contains a message in the name field It is widely believed that the term bluejacking comes from Bluetooth and hijacking. • However, a bluejacker doesn't hijack anything: he or she merely uses a feature on the sender and the recipient's device. Both parties remain in absolute control over their devices, and a bluejacker will not be able to take over your phone or steal your personal information. • Bluejacking is usually technically harmless, but because bluejacked people don't know what is happening, they think their phone is malfunctioning. • Usually, a bluejacker will only send a text message, but with modern phones it's possible to send images or sounds as well.
Most important security weaknesses • Problems with E0 • PIN • Problems with E1 • Location privacy • Denial of service attacks
Bluetooth’s Future • The future of this technology becoming a standard is likely • With a strong industry pushing behind it, success is inevitable. • Bluetooth will soon be known as Bluetooth 2.2 as they are trying to develop the product to better fulfill the needs of consumers • Often, with new technology, early changes mean reconstruction. Not With Bluetooth, instead, there will be an improvement to the existing standard.
The End • Thank You, for attending my presentation.
