lec04_24.pdf

ELEC S348F IoT Security Lecture 4: The IoT Device Layer Attack Surface Lecturer Tabitha Tao Chapter 4 - Sections & Objectives ▪ 4.1 Vulnerabilities and Attacks at the Hardware Layer Hardware Vulnerabilities Firmware Vulnerabilities ▪ 4.2 Threat Mitigation of the Physical Device Netw...

ELEC S348F IoT Security Lecture 4: The IoT Device Layer Attack Surface Lecturer Tabitha Tao Chapter 4 - Sections & Objectives ▪ 4.1 Vulnerabilities and Attacks at the Hardware Layer Hardware Vulnerabilities Firmware Vulnerabilities ▪ 4.2 Threat Mitigation of the Physical Device Network Access Control Concepts Encryption ▪ 4.3 Wireless Protocol Overview Bluetooth WIFI IEEE 802.15.4 4.1 Vulnerabilities and Attacks at the Hardware Layer Hardware Security Physical Vulnerabilities of Constrained Devices ▪ Constrained devices placed in remote locations physical security may be difficult to implement. ▪ Potential vulnerabilities : Theft of the device. Physical damage to the device. Disabling the device, removing power source. Disabling communication, disconnecting cables or other means of disruption. ▪ Provide a tamper proof or tamper resistant type of housing. Hardware Security Physical Device Security ▪ Sensor: be moved -> lose calibration Many smart sensors have the ability to trigger an alarm when they are not in proper adjustment. ▪ SD card: data stolen or destroyed by an attacker ▪ Standard surveillance and security protocols should be implemented as a first layer of defense. ▪ you should always have access to the device ▪ implement battery backup to power IoT devices in case of power outages. Hardware Security Hardware Vulnerabilities ▪ Wired magazine published an article in August 2017 - gain access to firmware on numerous IoT devices using eMMC flash and a $10 SD card reader. By soldering five wires to the eMMC flash chip and using a standard SD card reader the attacker was able to retrieve the firmware, operating system, and software on the chip and then save them to a PC. After the software is copied it can be examined for code vulnerabilities. ▪ Hardware vulnerabilities include: Shell access via the UART connection to an IoT doorbell. UART hack - a smart refrigerator provided access to a root shell when the system was rebooted. Hardware Security Hardware Vulnerabilities ▪ Other devices with hardware-based vulnerabilities that have been exploited include: Blu-Ray players Cameras Home automation devices Media players Music players NAS devices Printers Televisions VoIP hardware Medical devices Networking devices Android TV devices Hardware Security Lab – Investigate the FCC Database Firmware Vulnerabilities Firmware Vulnerabilities ▪ IoT devices require firmware to run. ▪ Firmware : embedded software, contains a minimal operating system and related programs ▪ Security vulnerabilities: firmware-related vulnerabilities for IoT devices are similar to those of other computers or networking devices. Firmware Vulnerabilities Firmware Vulnerabilities (Cont.) ▪ These vulnerabilities include the following: Default Login Credentials default login credentials were not changed. i.e admin/admin Change usernames and passwords to meet strong criteria before connecting Distributed Denial of Service (DDoS) attacks require botnets of infected systems hackers use automated script to log into remote devices and copy the infected software. Out-of-Date Firmware hacker will usually check if the firmware is out of date or look for unpatched exploits Firmware Vulnerabilities Firmware Vulnerabilities (Cont.) ▪ These vulnerabilities include the following: Buffer Overflow Attacks If the programmer does not account for the appropriate size of the input cause corrupt data, a denial of service, or could allow malicious code to run on the target system. Backdoor Installation after the attacker gains remote access attacker could run the netcat command and execute malicious commands remotely network diagnostic and testing tools can make the devices more exploitable if unauthorized entry occurs. Firmware Vulnerabilities Firmware Update Issues ▪ Updating IoT firmware and installing patches to fix security vulnerabilities are critical components of network security. ▪ IoT security has not kept up with the growth rate of IoT devices. patches do not exist for security vulnerabilities for devices device not be updatable or patchable ▪ IoT devices in an organization might number in the thousands or tens of thousands. realize challenge verify upgrades and patches source Firmware Vulnerabilities Firmware Update Solutions 1. keep a database of IoT devices and firmware information. 2. update firmware as soon as new releases come out 3. check the manufacturer’s website for updates on a regular basis 4. monitor or subscribe to security vulnerability services 5. have an automatic system for updating firmware and installing security patches 6. any firmware updates or patches are digitally signed and verified before installing Firmware Vulnerabilities Rooting an OS ▪ Rooting an IoT device - attacker followed a process that successfully granted him root access. ▪ Root access provides attacker complete control over that device. ▪ JTAG and UART interfaces are common attack vectors for gaining root access to the device. read the device’s memory and modify the firmware look for vulnerabilities and introduce new security holes. 4.2 Threat Mitigation of the Physical Device Network Access Control Concepts Access Control Models ▪ Different basic access control models： Mandatory access control (MAC) - the strictest access control used in military or mission critical applications provides users with access based on their security level clearance Discretionary access control (DAC) - allows users to control access to their data as owners of that data. Non-Discretionary access control - based on an individual's roles and responsibilities within the organization Attribute-based access control (ABAC) - based on attributes of the object (resource), the subject (user) accessing the resource, and environmental factors regarding how the object is to be accessed, such as time of day. ▪ Principle of least privilege - users should be granted the minimum amount of access required to perform their work function. /Privilege escalation exploit Network Access Control Concepts OAuth 2.0 Authorization Framework ▪ OAuth 2.0 Authorization Framework standardized protocol for internet-based authentication and authorization. access control of IoT devices to make them more secure by having a server handle the authorization of resources. Network Access Control Concepts OAuth 2.0 Authorization Framework (Cont.) 1. client sends authorization request to the resource owner. 2. resource owner sends back an authorization grant to the client. 3. client sends the authorization grant to the authorization server, requests an access token, and tries to authenticate. 4. authorization server validates the authorization grant and sends an access token back to the client 5. client sends the access token to the resource server to make a resource request. 6. resource server allows access to the requested resource Encryption Data and Password Security ▪ Encryption - ensure data confidentiality. ▪ Encrypting - applying an algorithm to data that will make it unreadable to those who are not authorized to see the information. ▪ should be encrypted : password, sensitive information ▪ Encryption for IoT data is critical because information being transmitted could contain sensitive information. ▪ IoT devices are vulnerable because many older IoT devices currently in production do not support encryption. Encryption Public Key Cryptography ▪ Cryptography ▪ Symmetric Cryptography - sender uses the secret key to encrypt the message, and the receiver uses the same secret key to decrypt the message. Challenge: secure key management. ▪ Public-key cryptography was introduced in 1976 by Whitfield Diffie and Martin Hellman in order to solve the secure key management problem. pair of keys: public key and private key - public key is published while the private key is kept secret Encryption Public Key Cryptography Encryption Public Key Cryptography Encryption Authorities and the PKI Trust System ▪ Public Key Infrastructure (PKI) with its Certificate Authority (CA) is needed to support large- scale distribution and identification of public encryption keys. PKI Certificate – Certificates contain an entity’s or individual’s public key. Certificate Store – Resides on a local computer and stores issued certificates and private keys. PKI Certificate Authority –signs these certificates using its private key. Certificate Database – stores all the certificates by the CA. Encryption Authorities and the PKI Trust System (Cont.) ▪ Bob has received his digital certificate from the CA. This certificate is used whenever Bob communicates with other parties. ▪ Bob communicates with Alice. ▪ When Alice receives Bob’s digital certificate, she communicates with the trusted CA to validate Bob’s identity. ▪ Challenge: large number of IoT devices is time-consuming and may be impossible to manage as more devices are added. 4.3 Wireless Protocol Overview Wireless Protocols Wireless Protocol Overview Bluetooth Wifi IEEE 802.15.4 Wireless Protocols Who is Bluetooth? Harald Bluetooth Wireless Protocols Bluetooth History Initially developed by Dr. Jaap Haartsen at Ericsson in 1994 Bluetooth 1.0 released in 1999 ○ The first mobile device launch in market was Sony Ericsson T36 Bluetooth 2.0 released in 2004 Bluetooth 3.0 released in 2009 Bluetooth 4.0 released in 2010 Bluetooth 5.0 released in 2016 Bluetooth 5.2 released in 2020 Wireless Protocols Bluetooth Bluetooth network topology Piconet Master can connect to 7 simultaneous or 200+ active slaves per piconet Unique hopping pattern/ID Scatternet High capacity system Minimal impact with up to 10 piconets within range Bluetooth network topology Piconet Connected in an ad hoc fashion One master and the others are slaves Each piconet has a unique frequency hopping pattern, decided by the master One master, up to 7 simultaneous slaves, up to 255 parked slaves Wireless Protocols Bluetooth Bluetooth network topology Form a piconet Master gives slaves its clock and device ID: Hopping pattern is determined by device ID Phase in hopping pattern determined by clock Addressing: Active Member Address(AMA, 3 bit) Parked Member Address(PMA, 8 bit) Bluetooth network topology Scatternet Linking of multiple co-located piconets through the sharing of common master of slave devices. A device can participate in multiple Piconets A device can be slave in one piconet and master of another Must synchronize to the master of the current piconet Wireless Protocols Bluetooth Bluetooth Address NAP:Non-significant Address Part (2 bytes). Contains first 16 bits of the OUI. -used in Frequency Hopping Synchronization frames. UAP:Upper Address Part (1 byte). Contains remaining 8 bits of the OUI. - used for seeding in various Bluetooth specification algorithms. LAP:Lower Address Part (3 bytes), allocated by the vendor of device. - identifies a Bluetooth device as part of the Access Code in every transmitted frame. Wireless Protocols Bluetooth Bluetooth States in the connection process: 1. Inquiry -- try to discover the others 2. Paging (Connecting) -- forming a connection between two Bluetooth devices, need to know the address found in the inquiry process 3. Connection -- enters the connection state: ○ Active Mode -- regular connected mode, where the device is actively transmitting or receiving data. ○ Sniff Mode -- power-saving mode, where the device is less active. It'll sleep and only listen for transmissions at a set interval (e.g. every 100ms). ○ Hold Mode -- temporary, power-saving mode. device sleeps for a defined period and then returns back to active mode The master can command a slave device to hold. ○ Park Mode -- deepest of sleep mode. A master can command a slave to "park", and that slave will become inactive until the master wake it up. Bluetooth Radio Layer Bluetooth operates in the 2.4GHz ISM band This is unlicensed but shared with other applications (Wi-Fi, baby monitors, microwave ovens, etc.) To ensure robustness to interference, signals are transmitted using a technique called Frequency Hopping Spread Spectrum (FHSS) Each transmission takes place on a different channel, peers switch rapidly between them Wireless Protocols Bluetooth Bluetooth Radio Layer 79 channels of 1MHz width, up to 1600 hops/sec Pseudo-random hopping sequence dictated by master, derived from the master clock and (part of the master device address), following a set of XOR and permutation operations Slot duration: 625us. A packet may occupy 1, 3, or 5 slots. Bluetooth Link Layer Data preceded by a 72-bit Access Code and 54-bit Header always transmitted at the basic rate (1Mb/s) 16-bit CRC computed on payload Payload and Header scrambled with a ‘whitening’ word (linear feedback shift register initialised with portion of master clock) - the idea is to avoid long sequences of all zero/one bits Sync Word: include Bluetooth Address Bluetooth frame format Exercise A slave wants to transmit 450 bytes of information using Bluetooth basic rate @ 1Mb/s. How long will it take? © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 40 Exercise A slave wants to transmit 450 bytes of information using Bluetooth basic rate @ 1Mb/s. How long will it take? Packet length: 72b (access code) + 54b (header) + 450*8b (payload) +16b (CRC) = 3,742b At 1Mb/s this would require 3,742us. © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 41 Exercise Slot size is 625us, Tx can occupy 1, 3, or 5 slots. That is 625, 1875, or 3125us. Packet cannot fit in 5 slots. How much info can you put into 5 slots then? 3,125b – 72b – 54b – 16b = 2,983b BUT max payload is 2744. So you need another transmission for 450*8 - 2744 = 856b of data With access code, header and CRC, this comes to 998b which is more than 1 slot but less than 3. In one slot you can put 625 – 72 – 54 – 16 = 483b © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 42 Exercise First transmission 5 slots (2,744b) – 3,125us Master polls – 625us Second transmission 1 slot (483b) – 625us Master polls – 625us Third transmission 450*8-2744-483 = 373b Add access code, header, CRC -> 72+54+373+16 = 515b -> 515us Total: 3,125+625*3+515 = 4,265us © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 43 Wireless Protocols Bluetooth Bluetooth Low Energy (BLE) Many similarities, but also a couple of differences Master == Central; Slave == Peripheral 40 channels, 2.4 GHz radio frequency The LE version provides much-reduced power consumption without sacrificing range. BLE connection set-up Device discovery much faster (periodic advertisement interval between 20ms-10.24s + a random delay between 0-10ms to avoid collisions) Four types of advertisement packets: ADV_IND – used by peripheral to requests connection to any central device ADV_DIRECT_IND - connection request directed at a specific central device. ADV_NONCONN_IND - Non connectable devices, advertising information to any listening device (beacons) ADV_SCAN_IND - Similar to ADV_NONCONN_IND, with optional additional information via scan responses. Wireless Protocols Bluetooth BLE connection set-up 1. If a connection request is accepted, a hop increment is agreed and the two peers hop accordingly, by adding increment to current channel index 2. A channel map can also be agreed, i.e. some channel scan be avoided. 3. The central also assigns a (private) address to a connecting peripheral, which is generated randomly 4. This access address will uniquely identify the physical channel between two devices 5. Hopping interval can also be renegotiated after connection set-up (energy saving). Wireless Protocols WIFI Wifi IEEE 802.11: responsible for developing wireless protocols ―Many standards Basic Service Set: the smallest building block BSSs connected via Aps(access point) Extended Service Set: two or more BSSs Wireless Protocols WIFI Wifi Security Wired Equivalent Privacy (WEP) Wi-Fi Protected Access (WPA) WPA2 Security level： WEP < WPA < WPA2 WEP - Wired Equivalent Privacy The original native security mechanism for WLAN provide security through a 802.11 network Used to protect wireless communication from eavesdropping (confidentiality) Prevent unauthorized access to a wireless network (access control) Prevent tampering with transmitted messages Provide users with the equivalent level of privacy inbuilt in wireless networks. Wireless Protocols WIFI WEP - Wired Equivalent Privacy Weak keys: It allows an attacker to discover the default key being used by the Access Point and client stations This enables an attacker to decrypt all messages being sent over the encrypted channel. IV (initialization vector) reuse and small size: There are 224 different IVs On a busy network, the IV will surely be reused, if the default key has not been changed and the original message can be retrieved relatively easily. Wireless Protocols WIFI Wi-Fi Protected Access (WPA) Replacement of security flaws of WEP Improved data encryption Strong user authentication Because of many attacks related to static key, WPA minimize shared secret key in accordance with the frame transmission Use the RC4 algorithm in a proper way and provide fast transfer of the data before someone can decrypt the data. WPA2 - WI-FI Protected Access 2 2 versions: Personal & Enterprise The primary enhancement over WPA is the use of the AES (Advanced Encryption Standard) algorithm AES or TKIP(temporal key integrity protocol ) Personal mode uses a PSK (Pre-shared key) & does not require a separate authentication of users Enterprise mode requires the users to be separately authenticated by using the EAP protocol Wireless Protocols IEEE 802.15.4 Overview ▪ The computational operating power constraints of many IoT things required new wireless protocols to be developed to enable things to communicate on networks. ▪ IEEE 802.15.4 protocol The IEEE 802.15.4 protocol was originally developed for use in personal area networks (PANs). 802.15.4 consists of media access layer (MAC) and physical layer (PHY) and specifications. Wireless Protocols IEEE 802.15.4 Device Roles Full Function Device (FFD) –operate as a PAN coordinator and communicate with any other device. Personal Area Network (PAN) Coordinator - One FFD is designated as the PAN coordinator for the WSN. Reduced Function Device (RFD) – simple devices can only communicate with FFDs or the PAN coordinator. RFDs can never act as the coordinator. © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 55 Wireless Protocols IEEE 802.15.4 Topologies Star Topology Mesh Topology Cluster Tree © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 56  IEEE 802.15.4 Topologies Star Topology ○ All devices communicate with PAN coordinator ○ PAN coordinator : fixed power supply ○ other devices: battery powered  IEEE 802.15.4 Topologies Mesh Topology ○ any device can communicate with any other device in range ○ ad hoc, self-organizing, and self-healing  IEEE 802.15.4 Topologies Cluster Tree Topology Topology ○ most devices are FFDs ○ RFD connect as a leaf node at the end of a branch ○ Any of the FFDs can act as a coordinator and provide synchronization services ○ Only one PAN coordinator Wireless Protocols IEEE 802.15.4 Security Access control ▪ 802.15.4 uses symmetric key cyphers for prevents unauthorized devices encryption. Symmetric keys are less secure then from joining the network. asymmetric, or public key, cryptography. Message integrity protects against alteration of data while it is in transit by using an encrypted cryptographic key. Message confidentiality prevents threat actors from reading the transmitted data. Replay protection Legitimate messages can be captured and sent out on the network at a later time © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 60 Wireless Protocols Mesh Protocols that use 802.15.4 ▪ 6LoWPAN – This protocol provides IPv6 services to low power devices in PANs. It can be added to other protocol stacks such as Zigbee and Thread. It provides header compression and IPv6 addressing services. ▪ WirelessHART –an international wireless specification (IEC 62591) for the Industrial Internet of Things (IIoT). ▪ ISA 100.11a – This is a U.S. standard for communication on the IoT. does not stipulate an application layer and uses 6LoWPAN and User Datagram Protocol (UDP) for its network and transport layers. Wireless Protocols Other Wireless Options ▪ Other wireless protocols have been developed that support low power wide area networks (LPWAN). ▪ LoRa is one of a number LPWAN technologies and has become popular due to its low cost and wide implementation. ▪ LoRaWAN - The Things Network is an international organization which enables development of IoT proof-of- concept systems using the LoRa radio physical layer and LoRaWAN data link, and network layer elements of the protocol stack. The Things Network encourages individuals to create and maintain their own LoRaWAN gateways. ▪ Cellular - Cellular data standards, known as 3GPP, are implemented to extend IoT networks, but with devices that have a fixed power supply. Current cellular data services are not well suited to IoT applications due to power constraints. The fifth generation (5G) cellular specifications include LTE Advanced for Machine-Type Communication (LTE MTC). This technology includes features that greatly improve power consumption while providing simplified device capability for small periodic data transmission. Narrowband IoT (NB-IoT) is a low- power low-bandwidth protocol especially for indoor applications. It uses a portion of a wireless LTE carrier's frequency spectrum. 4.4 Chapter Summary Chapter Summary Summary (Cont.) ▪ Network access control concepts A security analyst should understand the different basic access control models to have a better understanding of how attackers can break the access controls. The OAuth 2.0 Authorization Framework can be used for access control of IoT devices to make them more secure by having an authorization server handle the authorization of resources. IoT device identity management should handle IoT device access to other information from other resources in addition to handling access to that device's resources. ▪ Encryption Encryption for IoT data is critical because some of the information being transmitted could be sensitive. Most IoT devices do not have the processing power or resources necessary for the more robust encryption algorithms. Implementing public key cryptography into IoT devices is the recommended method to ensure IoT device security. PKI is used to prove the identity of the IoT device. Summary ▪ 4.1 Vulnerabilities and Attacks at the Hardware Layer Hardware Vulnerabilities Firmware Vulnerabilities ▪ 4.2 Threat Mitigation of the Physical Device Network Access Control Concepts Encryption ▪ 4.3 Wireless Protocol Overview Bluetooth WIFI IEEE 802.15.4