Quiz 8- Securing IoT

Flashcard set on lectures 20 and 21

Radio Frequency Identification

RFID stands for…

Near Field Communications

NFC stands for…

Europay Mastercard and Visa

EMV stands for…

RFID

Primarily used in inventory control, e.g. tracking packages

NFC

Primarily used in mobile devices, e.g. contactless payments on your phone

EMV

Primarily used in payment systems, e.g. contactless credit cards

Card emulation mode

The NFC device acts like a normal passive contactless card, emulating a smart card.

Reader/Writer mode

The NFC device acts like a normal active contactless card reader. It can then generate RF fields to communicate with contactless cards, RFID tags or NFC Forum tags.

Peer to Peer Mode

Two NFC devices can communicate together in both active or passive NFC mode. The initiator or master initiates a data transfer and waits for the target or slave to respond.

Differences between NFC and RFID

• While NFC on a smartphone can emulate an RFID tag behavior, they can support additional operations, since the phone is a computing device.

• NFC does not have the same hardware protections as RFID (more on this later)

True

True or False: RFID tags typically do not have battery.

True

True or False: RFID needs power to perform functions like:

• Sending radio signals to a reader

• storing and retrieving data

• performing other computations (e.g. those needed for security mechanisms)

Origins of power for RFID

• Uses the electromagnetic energy it receives from a reader’s transmission to reply to the reader

• Reply signal, also known as the backscattered signal, has only a fraction of the power of the reader’s signal.

False; cannot

True or False: An RFID tag can initiate communications on its own.

Active tag (RFID)

• Has a battery that is used to communicate to the reader, to power on-board circuitry, and to perform other functions

• Longer distance, more operations

Semi-active tag (RFID)

• Has a battery, but unlike active tag, remains dormant until it receives a signal from the reader to wake up

• Longer battery life span than active tag

Semi-passive tag

• Has a battery, but only used to power on-board circuitry for other purposes

  • E.g. monitor temperature

• Has same communications as passive tag, i.e. backscatter

further; more

In RFID, higher the frequency (i.e. UHF), the signals can travel ____ and carry ____ data.

Penetrate through substances

In RFID, lower the frequency (i.e. LF), the better signals can  ____ ____ ____.

Eavesdropping for RFID

• Reader →  Tag is called forward channel

• Tag → Reader is called back channel, or backscatter channel, or reverse channel

• Remember reader powers the tag

• So forward channel is typically stronger than the back channel

Normal operating range

This is distance legitimate operations are expected to occur

Back channel/Forward channel eavesdropping range

Distance adversary reader can reliably hear the tag (reader) message

Rogue scanning range (eavesdropping)

Distance which adversary reader can reliably communicate with tag (no limit on reader power)

Rogue command range (Eavesdropping)

Distance over which adversary reader can execute a tag command (do not required to receive tag response)

Foreword channel analysis range (Eavesdropping)

Adversary reader can detect presence of reader’s signal (without reliably interpret content)

Cover coding

• This is a kind of “encryption” that is cheaper than conventional encryption

• Makes use of the mismatch in reader → tag and tag → reader communications

Cover-coding steps

• Step 1. Reader sends message to tag requesting a key

• Step 2. Tag replies with random 16-bit number (i.e. the key)

• Step 3. Reader XORs message with this key to produce “ciphertext” and sends to tag

• Step 4. Tag applies XOR to “ciphertext” and the key to obtain the message

False

True or False: Cover-coding can still work if an adversary can overhead the key in step 2.

True

True or False: Tag → reader communications are weaker in cover-coding, and hence harder to overhead.

Relay attack

Message from one location is relayed to another location to make it appear closer than it really is.

False (Explanation: Relay attack is just “relaying” an action elsewhere, you don’t need to read any data)

True or False: Strong encryption can prevent a relay attack.

Why relay attacks are easy

• Problem is that it does not verify that the correct key is in physical proximity

  • It only verifies if can communicate with the correct key

• Assumption that ability to communicate implies physical proximity

Physical shielding of key

Name one individual countermeasure for a relay attack.

Design countermeasures for relay attack

• Re-design to more active (e.g. push button, a switch) (for car keys)

• Time outs

Cloning attack

• Adversary attempts to create a new tag F (fake) that mimics the real tag O (original)

• Query O for data, and then write that data into F. Then affix F onto product, e.g. packages, documents, etc.

Cloning attack

• TID is a number that is permanently written to one specific part of the memory of an RFID tag

• Idea is that every tag will have its own unique TID number that is written at point of manufacture

• So while adversary can read the TID from O, cannot overwrite value in F

(Assumes that ALL manufactures enforce this feature, or adversary cannot make their own tags)

False (Explanation: Malicious tag can behave the same way as compliant tag)

True or False: It’s easy to verify TID in an RFID tag.

True

True or False: TID cannot be overwritten

E0h

Class of TID that uses manufacture ID and 48-bit serial number

E2h

Class of TID that uses manufacture ID and model info.

Singulation (Query)

The process by which a reader identifies a particular tag

• E.g. when a reader issues a command to modify a tag’s memory, neighboring tags should not accidentally execute the same command

Query

• Common C1G2 standard uses the following process (summarized)

• Reader broadcast to all tags a range of slots

• Each tag return random number in one slot

• If no collisions, reader acknowledges, and then tag replies with ID

• Can then accept commands, e.g. remain silent so that other tags can reply, etc.

All tags will recieve reader’s query; collisions

What happens when there are a lot of tags in a query? Then what?

Privacy attack

(Just a flashcard to read, answer with “privacy attack”)

• RFID tags do support password for certain operations like Lock and Kill

• Some tags support password for Read and Write operations as well

• Not the same as traditional passwords. Once deployed onto tag, not changed.

• Reality check. The number bits for the password is limited. 32 bits, 48 bits

Jamming/DoS attacks

• Exploit the kill command

• The kill command will permanently disable the tag from responding to a reader

• This command is protected with a 32-bit password

• How many combinations to brute force?

• Conventional defenses against brute force attacks to not work

Jamming/DoS attacks

• What happens if adversary device mimics a tag but does not adhere to the protocol?

  • Adversary no longer dependent on overpowering sender/receiver signal

  • Conventional defenses against isolating adversary device may not work

EMV Step 1

• Initialization

• POS gets basic information about user’s payment device, e.g. account number, expiration date, etc.

• Device can also get some info. from POS (e.g. amount, country code, etc.) This is optional

EMV Step 2

• Authentication of user’s device and user

• Provides protection against counterfeit user payment device

• Step 2 is optional. Possible that user’s device and POS cannot execute this

• Supports 3 different authentication methods

Static Data Authentication (SDA) (EMV step 2)

• Card provides some digitally signed data (e.g. the card number and expiry date) to the terminal to authenticate itself using known PK

• Vulnerable to cloning, since this signature is fixed

Dynamic Data Authentication (DDA) (EMV Step 2)

• Requires card/device to be to execute asymmetric crypto and have a public/private key pair

• First send certificate to POS, then challenge and response

• Expensive

Combined Data Authentication (CDA) (EMV Step 2)

• Similar to DDA, except using private key to sign other messages

• DDA only use private key to authenticate device, but not for subsequent messages

EMV Step 3

• Authentication of user

• Previous step was the payment device. Provides protection against lost or stolen user’s payment device

• Here is authentication of user

• Many different options

Options that can be used in EMV Step 3

• Use PIN

  • Online. POS will check with user’s bank

  • Offline. User’s payment device will check with memory

• Physical signature

  • User signs on printout

• PIN and signature

  • Combination of the two

• No verification

  • Supposed to be for NFC.

  • Executed quickly, limited to small amount

EMV Step 4

• Actual transaction is executed

• Online. User’s device sends message to POS, which relays it to the bank. If approve, send message to POS

• Offline. User’s device sends proof to POS, which is then sent to bank later.

• Choice depends on POS, but user’s device can decline