track 5 session 2 - st dev con 2016 - security iot best practices

October 4, 2016

Santa Clara Convention Center

Mission City Ballroom

IoT Security Good Practices

Joe Pilozzi

In the News2

Invasive Product AttacksWith the case opened / removed

• Test / debug port access

• Inter device bus and IO probing

• Reset, clock attacks

• Power analysis

• Temperature / electrical attacks

Non Invasive AttacksMisuse of network protocols

• Exploit communication protocol errors

• Flaws in software design / implementation

Invasive Silicon AttacksDevice de-packaged

• Circuit analysis and probing

• Fault injection

Solutions 3

Box InternetThe

Cloud

BOXAdd a Secure Element• Much Better Tamper Resistant

• Trusted Crypto Services

• Secure Storage

• Independently Certified

A Better

Solution

Use an MCU’s security features• Unique Device IDs

• Memory Protection

• Firewall

• Tamper Detection

• Crypto Hardware

• AES, T-RNG

• Debug Port Protection

Solution

SOLUTIONS

It’s All About Risk Management 4

• Understand the value of the Assets you are going

to protect, taking into account all stake holders

• Understand your Threats and Vulnerabilities

• Develop a security strategy to reduce Risk, using

right level of security for the value of the Assets

being protected

• Make use of the integrity and cryptographic tools

available

Fortified Solutions

Fortifying an IoT Device

Example Of A Simple IoT Device 6

Sensor MCU

Communications

Device

STM32

Communication

Device

Sensor

MCU Secure

Element

STSAFE

Secure Element

An IoT Device’s Security Needs 7

Prevent device misuse

Prevent device or server counterfeiting

Resistance against

hacking, cloning

Authentication• Device to device

• Device to server

Service and network access corruption

Prevent device

misuse

Integrity and Availability• Secure Boot

• Secure firmware upgrade

• Trusted processing

Data privacy

Prevent data collection or corruption

Confidentiality• Data / identity protection

• Secure communications

• Secure storage

UpgradabilitySecure Communications• Secure firmware upgrade

Prevent device misuse

Need Solution

Product Integrity and Cryptography

• Cryptographic methods are used to:

• Protect the Confidentially and Integrity of data / information

• Ensure a chain of trust through Authentication

• Product integrity, availability and resistance against attacks

• Uses cryptography and stateful processes to ensure correct operation

• Uses hardware to enforce rules and countermeasures

• Uses tamper proof methods to mitigate attacks

8

Cryptography

CryptographyThe art of hiding things

• Cryptographic ciphers have been used for centuries to protect

information between communicating parties

• Cryptographic processes are mathematical algorithms that provide:-

• Encryption to keep information Confidential during communications

• Authentication to validate information, identities and trust individual items

• Underpins a platforms Integrity processes, like Secure Boot

10

Secret Key

Cryptography

(Symmetric)

CryptographyOne Key or Two ?

11

Data File Data FileData File

Clear Text Clear Text

Cipher Text

Encryption Decryption

Sender ReceiverCommunications

Channel

Public Key

Cryptography

(Asymmetric)

Data File Data FileData File

Clear Text Clear Text

Cipher Text

Encryption Decryption

PrivatePublic

CryptographyCharacteristics

• Symmetric – or single (or secret) key

• Use fewer compute resources and are faster

• Used to protect data - during communications or while at rest

• Issue with sharing and managing keys

• Algorithms like AES and TDES

• Asymmetric – (a key pair - public key + private key)

• Provides easier key sharing and management using a Public Key Infrastructure (PKI)

• Algorithms are more complex, hence compute intensive, thus lower performance

• Used for authentication, key exchange, digital signatures and certificates

• Algorithms like RSA and ECC (Elliptic Curve Cryptography)

12

CryptographySize Matters

• NIST recommended key sizes

13

Symmetric RSA ECC

56 512 112

80 1024 160

112 2048 224

128 3072 256

192 7680 384

256 15360 521

• Bigger is better - stronger

• ECC uses a smaller key for the same strength

as RSA

Str

en

gth

STRONG

CryptographySize Matters

• Just a thought …

… that’s one small key in a huge hay-stack !

14

Estimated number of 1050 atoms

166 bit

Symmetric Key

≈With ~10^50

combinations

CryptographyHash Algorithms

• Cryptographic Hash

• An easy to compute, one-way cryptographic function that generates a result which for all

intents and purposes is unique for any given message or file :-

• Unalterable (practically impossible to modify the original file or message without causing the result

to be altered)

• The resultant hash value is always the same length irrespective of the size of the message or file

• Used in many processes like authentication, secure boot, secure firmware down-loads

• NIST (Secure Hashing Algorithm) SHA-1, SHA-2, SHA-3

15

Cryptographic Hash FunctionData FileCode File

Clear Text

Hash Value

One Way Function

Hash function has no key, and the

clear text can not be recovered from

the hash value

CryptographySignatures

• Digital Signatures

• Used to check the authenticity of information, code, files, messages, and Public Keys in the case of

Digital Certificates

16

Sign / Encrypt

Code Signing Code File

Clear Text

Hash Hash Value

Private

Using RSA

Verify / Decrypt

Code Authentication

Public

Hash Value

Code File

Clear Text

Hash Calculated Hash Value

Compare If the Hash values are

equal the code is authentic

Using RSA

Random Number Generator (RNG)• Random Number Generators are typically used :-

• To generate a challenge during authentication process, a seed for keys, digital signatures

17

http://www.random.org/bitmapsPHP rand() on Windows

http://boallen.com/random-numbers.html

http://en.wikipedia.org/wiki/Random_number_generator_attack

• A source of entropy (randomness)

for the crypto math

• Statistical properties of the RNG’s

output is used to evaluate level of

randomness

• A non random or predictable output

is a source weakness

Random Number Generator (RNG)

• A Pseudo Random Generator uses a software algorithm to generate

numbers

• A True Random Generator makes use of the unpredictable physical

properties of silicon to generate its numbers

• Use RNG’s complying with NIST FIPS 140-2 Annex C

18

• Always make use of a True Random Generator

Cryptography 19

• Not all crypto libraries are the same …

• Is it from a reputable source ? or is it freeware ? open source ?

• Does it come with any warranties or certifications ?

• Do you know its history, is it maintained?

• Does it have a track record of fixing security issues ?

• Silicon vendor libraries specifically make use of hardware accelerators or

are designed to execute in a secure partition or environment

Libraries

• Take care where you obtain cryptographic libraries from

• Use libraries that come from reputable sources

• Use libraries that make use of hardware accelerators or are partitioned to

execute in a secure manner

Cryptographic Accelerators

• Cryptographic accelerators are specific hardware engines that off-load

cryptographic functions from the CPU

• Providing higher data through-put performance, and lower power

• Greater integrity – more resilient against system and board level software attacks

• Often supporting secure key ladders, secure key stores or caches

• The cryptographic functions are intrinsically bound to the device

• Functions typically performed

• AES, TDES, SHA, RSA, ECC, SHA-1, SHA-2, SHA-3

20

• Use hardware Cryptographic Accelerators

when available

Integrity and AvailabilityResilience to Attacks

Root of Trust

• An anchor point for cryptographic services bound with a device

• It may be embedded in the Microcontroller or a Secure Element

• Performs stateful, trusted, cryptographic processes

• Is the first process to start after reset

• Often ROM (locked Flash) based as integrity is important

• May use hardened logic design that is tamper resistant

• Performs code authentication; acts as the First Stage in a Secure Boot

process

22

Secure Boot

• To ensure a products integrity code should be authenticated before it is run

• Secure boot uses cryptographic functions to confirm the authenticity of a

code image before allowing it to execute

• A multi-stage secure boot process, is one where each stage authenticates

the next, hence a chain of trust

23

First Stage

Code

Cert.Reset

Chain of Trust

Second stage

Loader

CodeCert.

Authenticates

Trusted

Third Stage

RTOS

CodeCert.

Authenticates

Application

Authenticates

Secure Boot

• The Secure Boot process

• Performed after a reset, using a Public key stored in the device

• It is a stateful process for predictable behavior

• Its code should be stored in ROM or locked Flash

• A Root-of-Trust may be used to performed this process

24

State based process

Reset

Trusted

Verify / Decrypt

Code Authentication

Public

Hash Value

File

Code Image

Hash

Calculated Hash Value

Compare

OK

NOK

Reload

Run Code

• Code images may also

be encrypted

• Protect your private

signing key!

Protect Assets and Keys 25

• Sensitive data should be encrypted when not being used

• Sensitive applications data, confidentiality, privacy, customer financial and health info.

• Trusted root keys (symmetric keys or asymmetric Private keys)

• Access to this data must be carefully controlled and restricted to authorized

persons and processes

• Lock down Public keys and certificates

• They don’t need to be encrypted only immovable - locked to the platform

• Only allow replacement through a cryptographic process

Secure Storage – Data at Rest

• The key to success is to protect your keys

• Don’t allow unauthorized access to keys

Secure Communications 26

• The IoT ecosystem relies on confidential and trusted communications

• Use a cryptographic authentication process to establish trust

All devices should be uniquely identified and able to verify the identity and authenticity of other

communicating devices

• Public Key Infrastructure (PKI) standards

• RSA, ECC

• Use end-to-end encryption

• Ciphers: AES, TDES

Data in Motion

• Make use of established secure communication protocol standards

• Secure Socket Layer/Transport Layer Security (SSL/TLS),

• Datagram TLS (DTLS)

Application Data 27

• Handle confidential and sensitive data securely when being used

• Segmented processing

• Uses memory protection or firewall mechanisms to segment memory and code execution into secure

and non secure zones

• Requires a clear understanding of software and hardware to develop a partitioned solution

• Dual mode CPU’s – Trusted processing

• Provide context switching between “trusted” and “untrusted” processing

• Simplifies the partitioning and development of secure processes

• Secure Processing using a Secure Processor, like ST’s STSAFE

• Provides the highest level tamper resistance for protecting cryptographic services and keys

Data In Use

Layers of Security Services 28

• Security services should be handled

independently in silo’ed processes

System Layers

Application / Cloud• Access control and right management

• Feature and product management

Data / Transport Layer• TLS/DTLS, HTTPS etc

Link Layer / Physical Layer• Network physical layer security

• e.g. WiFi – WPA2, 802.11i

Device Security Services

• Secure Boot

Debug Ports

• Debug ports, like JTAG, represent any easy access route for hackers

• Remove test headers, debug access points from the board

• Remove from code any debug processes as these could be exploited

• This includes potential boot-loader paths (UART, SPI, I2C, USB, etc.)

• Restricted access to production keys

• Only use test or dummy keys while the product is in debug mode

29

• If the device has a lockable debug port – don’t forget to lock it!

Life Cycle

Product Life Cycle 31

Definition

Design

Development

Prototype / Test

Decommissioning

Product Launch

Maintenance

• Define the product and identify the

Assets you plan to protect

• Design the product based on the

correct level of security

• Develop methods and processes

to protect those Assets over the

entire life-cycle

• Develop secure processes to

handle firmware throughout the

products life-cycle

• Product security should be factored

in from day-one

Do Verify Your Implementation

• Today’s largest threats are through software based attacks

• Used defensive coding practices and tools to detect possible vulnerabilities

• Review carefully the trustworthiness of code coming from external sources

• Check that all the latest security patches are being used

• Analyze code to remove debug and native firmware loading interface capabilities

• Use code integrity checking techniques like Secure Boot, Secure Firmware Update

• Rigorously test and support interoperability workshops

• You may also use Security Assessment Services

• Provide independent security assessment of products and ecosystems

• Support standards compliance evaluation and certification

32

Security Partnerships

• Use trusted partners throughout your value chain – protect your

products, services and brand

• Use partners equally committed to security and integrity

• Select partner provided schemes, processes and solutions that allow

you to securely provision and update your products firmware in

untrusted environments

33

Conclusions / Recommendations

Trusted IoT Platforms Do Matter ! 35

Who’s Watching your loved ones !

Source Engadget

Recommendations 36

• Internet of Things presents a wealth of opportunities and growth for business. It also represents

increased opportunity for theft, mischief and damage or even loss of life

• Reduce risk by designing and managing products fortified against attacks

• Hackers will go after the weakest links in a system not necessarily directly to their target

• Understand the value of assets for all the stake holders in your solution

• Perform a Threat analysis to better understand your Risks

• Remember Confidentially, Availability and Integrity are key

• Using these good design practices to develop and maintain secure products

• Design a products resilient against attacks through out its whole life-cycle

• Products robust can achieved through use of security features and tools

• Work with trusted and experienced partners throughput your value chain

Work with ST,

your experienced

partner

Demos

ST Solutions for Security in IoT 38

Smart City Solution

for IoT Node

39

Thank You