OUR ROAD TO IOT: SECURE DEVICE GRID 5 October 2015 Kresten Krab - - PowerPoint PPT Presentation

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OUR ROAD TO IOT: SECURE DEVICE GRID 5 October 2015 Kresten Krab - - PowerPoint PPT Presentation

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OUR ROAD TO IOT: SECURE DEVICE GRID 5 October 2015 Kresten Krab Thorup @drkrab Introduction IoT and SSL/TLS landscape Secure Device Grid design Lessons Learned ABOUT THE SPEAKER Kresten Krab Thorup, Ph.D. Trifork CTO - since 1999

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5 October 2015

OUR ROAD TO IOT:
 SECURE DEVICE GRID

Kresten Krab Thorup @drkrab

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Introduction IoT and SSL/TLS landscape Secure Device Grid design Lessons Learned

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ABOUT THE SPEAKER

Kresten Krab Thorup, Ph.D. Trifork CTO - since 1999 JAOO, QCon, YOW!, GOTO Conferences Language Hacker

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HOW TO REMOTE CONTROL YOUR IOT DEVICES?

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IOT REMOTE CONTROL

ACCESS Device/Mobile behind NAT SECURITY Secure Traffic (Secrecy, Integrity) Authentication Privacy

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DESIGN #1

GATEWAY MOBILE DEVICE

TRUSTED?

MAN IN THE MIDDLE

FIREWALL FIREWALL

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DESIGN #2

GATEWAY MOBILE DEVICE

END-TO-END TRUST

FIREWALL FIREWALL

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DESIGN #2

GATEWAY MOBILE DEVICE

PAIRING





KEY EXCHANGE PIN

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DESIGN #2

GATEWAY MOBILE DEVICE Secure Authenticated Private

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HOW TO SECURE THIS?

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PUBLIC KEY CRYPTOGRAPHY

SecretKey PublicKey

Alice Bob

I’m Home! SecretKey PublicKey

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ENCRYPTION

Alice Bob

ciphertext

encode(“I’m Home!”, PublicKey) decode(ciphertext, SecretKey)

Only Bob can decode it

Eve

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SIGNING

Alice Bob

signed

sign(“I’m Home!”, SecretKey) verify(signed, PublicKey)

Only Alice could have created the signed message

Eve

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TRUST

Alice Bob Eve Carl

PublicKey PublicKey sign(PublicKey, 
 SecretKey) sign(PublicKey, 
 SecretKey)

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SSL/TLS

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SSL/TLS

Standardized approach to Public Key Crypto Public Key Infrastructure (CA’s) Standard Protocols 15+ years of history

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SSL/TLS

iOS Android Windows OpenSSL ARM Broadcom WinCE GATEWAY

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Many platforms ⇒ weakest link defines level PROBLEMS Implementation errors / limitations Protocol errors Configuration/use errors

SSL/TLS WOES

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NATIVE STACK LIMITATIONS

Client certificate capability Validate/control connection status? Who are you connected to? Support proper (modern) ciphers

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WELL KNOWN SSL/TLS BUGS

FREAK - downgrade to ‘export grade’ crypto POODLE - downgrade makes keys guessable HeartBleed (OpenSSL)- expose contents of server memory Logjam - Exploits standard config (DH) params Many individual implementation bugs

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TLS VULNERABILITIES

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SSL VULNERABILITIES

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LESSON #1 IMPLEMENT UPGRADE OF SOFTWARE IN THE FIELD

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LESSON #2 OPENSSL IS A ATTACK TARGET
 BECAUSE IT IS POPULAR

(Just like Windows)

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COMPLEXITY

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TLS COMPLEXITY

Creeps in as standards develop 15+ years backwards compatible ASN.1, X509 Certificates, Revocations, … Protocol negotiation (and renegotiations) Diversity of features available on platforms Diversity of configurations

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DIVERSITY

iOS Android Windows OpenSSL ARM Broadcom WinCE

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OUR TLS SOLUTION

OpenSSL OpenSSL OpenSSL OpenSSL OpenSSL OpenSSL OpenSSL

ONE CONFIGURATION: TLS 1.2 ECC BrainPool P384 One cipher ECDH_ECDSA_AES

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LESSON #3 ANY SSL/TLS IMPLEMENTATION
 IS LARGE AND COMPLEX

(ARM JUST OPEN SOURCED 
 A NEW STACK ‘mbed TLS’)

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A NEW START:

GOING SMALL

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A NEW START: NACL (CURVE 25519)

Crypto library from Daniel Bernstein (of qmail fame) Used in ZeroMQ, Tor, SSH, HomeKit, AirPlay, Chrome/QUIC, countless open source tools. 
 “An attacker who spends a billion dollars on special- purpose chips to attack Curve25519, using the best attacks available today, has about 1 chance in 1027 of breaking Curve25519 after a year of computation.”

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NACL: CRYPTO SIMPLIFIED

One way to do things ECC crypto (Curve25519) Stream cipher (Salsa20) SHA25 CurveCP: Control Protocol (like SSL/TLS)

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NACL: CRYPTO SIMPLIFIED

Multiple implementations NaCl, the original (compiles to ~30k ARM code) libsodium (with fast ASM for popular platforms) TweetNacl, compiles to 10k ARM code Java, .NET, JavaScript, … you name it.

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NACL: WHAT’S NOT THERE?

Key Management Certificate Chains / X509 / ASN.1 Protocol negotiation, downgrade, … Many ciphers, hashes, … RANDOM SOURCE

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LESSON #4 WHEN YOU CONTROL BOTH ENDS, CONSIDER SIMPLIFYING

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RANDOM

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LESSON #5 RANDOMNESS IS HARD IN
 EMBEDDED DEVICES

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RANDOM IS HARD

Initialize when product is ‘installed’ at factory product’s public key entropy data file Recent JEEP hack was lack of entropy Android also had a serious random bug in 2013

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PRIVACY

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PRIVACY

GATEWAY MOBILE DEVICE

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NEED-TO-KNOW

Gateway/router has no knowledge of peer identity — It only knows that they trust each other A break-in of cloud infrastructure does not compromise peers Individual peers being compromised will not compromise other peers.

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LESSON #6 SAVE ONLY WHAT’S NECESSARY

(PRIVACY BY DESIGN)

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TRUST SCHEMES?

Establish trust by means of a 3rd party SMS 3rd party SSO Certificate authority Trust direct between devices

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TRUST

Alice Bob Eve Carl

PublicKey PublicKey sign(PublicKey, 
 SecretKey) sign(PublicKey, 
 SecretKey)

Carl2

sign(PublicKey, 
 SecretKey) sign(PublicKey, 
 SecretKey)

Carl3

sign(PublicKey, 
 SecretKey) sign(PublicKey, 
 SecretKey)

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TRUST

SecretKey PublicKey

Alice Bob

SecretKey PublicKey OTP OTP

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LESSON #7 AVOID CERTIFICATE AUTHORITIES
 (CA’S) WHEN POSSIBLE

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TRUST ON FIRST USE

SSH shows a fingerprint to verify on first use Our product you enter a PIN to verify the peer Henceforth, trust the holder of that key

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END-TO-END LIMITATIONS

Sometimes you want an OPEN API

  • Most web-enabled IOT devices do that

IFTTT (open programmable interation platform)

  • Holds on to all your credentials
  • Email, google, facebook, devices, …
  • Ideal targt for a hacker

Make this a special case, not the default.

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SUMMARY

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SUMMARY

SSL/TLS is more complex than you think CA’s introduce trust in 3rd parties Implement software upgrade Control both ends? Consider a simpler solution. Randomness is hard Remember (log/store) only what’s necessary

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SLIDE 55 Aarhus Copenhagen Zurich Amsterdam Berlin Budapest Buenos Aires Krakow Leeds London San Francisco Seattle Stockholm
  • ur product

securedevicegrid.com

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SLIDE 56 Aarhus Copenhagen Zurich Amsterdam Berlin Budapest Buenos Aires Krakow Leeds London San Francisco Seattle Stockholm

Kresten Krab Thorup

krab@trifork.com @drkrab