Best Practices for IoT Security in the Cloud

© 2015, Amazon Web Services, Inc. or its Affiliates. All rights reserved.

John RotachSoftware Development Engineer – AWS IoT

October 27, 2016

Best Practices for IoT Security in the Cloud

All things around us are getting connected

All things around us are getting connected

Things will proliferate

2013 2015 2020

Vertical IndustryGeneric IndustryConsumerAutomotiveMany

Some

Lots

Connected ≠ Smart

Internet 1985 IoT 2016

Gopher HTTP

FTP MQTT

NNTP CoAP

Telnet XMPP

Archie AQMP

In reality, it is even more complex

Layer Standards

Application HTTP, MQTT, AMQP, CoAP, XMPP

Network IPv4, IPv6, 6LoWPAN, ZigBee, Z-Wave, Insteon

Physical Ethernet, CAN, USB, 802.11, Bluetooth, 802.15.4, SPI

But my data isn’t sensitive!

Why do IoT at all?

Changes happen inthe realworld!

The Risk

Changes happen inthe realworld!

Bad

A Simple Goal

Requirements

Secure Communications with ThingsStrong Thing IdentityFine-grained Authorization for:

ThingsPeople

The System

DynamoDB LambdaKinesis

The System

DynamoDB LambdaKinesis

The System

DynamoDB LambdaKinesis

The System

DynamoDB LambdaKinesis

Requirements

Secure Communications with ThingsStrong Thing IdentityFine-grained Authorization for:

ThingsPeople

Network Traffic Is Complex

04:07:18.045065 IP 85.119.83.194.1883 > 10.0.0.67.51210: Flags [P.], seq 1586864891:1586864913, ack 820274045, win 227, options [nop,nop,TS val 2390025928 ecr 577393885], length 22 0x0000: 4500 004a 3694 4000 2d06 639e 5577 53c2 0x0010: 0a00 0043 075b c80a 5e95 a2fb 30e4 637d 0x0020: 8018 00e3 66cd 0000 0101 080a 8e74 e6c8 0x0030: 226a 54dd 3214 0007 666f 6f2f 6261 7200 0x0040: 0454 656d 703a 2038 3346

Network Tools Are Up To It

MQ Telemetry Transport Protocol Publish Message 0011 0010 = Header Flags: 0x32 (Publish Message) 0011 .... = Message Type: Publish Message (3) .... 0... = DUP Flag: Not set .... .01. = QOS Level: Acknowledged deliver (1) .... ...0 = Retain: Not set Msg Len: 20 Topic: foo/bar Message Identifier: 1 Message: Temp: 83F

Mutual Auth TLS

Mutual Auth TLS

Mutual Auth TLS

Requirements

Secure Communications with ThingsStrong Thing IdentityFine-grained Authorization for:

ThingsPeople

What are Certs and Keys?

Certificate – Public identityPrivate Key – Private proofRoot CA – Validate

rootCA

Elliptical Curve Cryptography (ECC)

ECDHE-ECDSA-AES128-GCM-SHA256ECDHE-RSA-AES128-GCM-SHA256

Elliptical curve logarithm vs RSA integer factorizationSmaller key sizes for same securityECDHE – key exchange algorithm (forward secrecy with ephemeral keys)ECDSA – signature algorithm with EC private keys (authentication)

AWS-Generated Keypair

CreateKeysAndCertificate()

Actual Commands

$ aws iot create-keys-and-certificate --set-as-active{ "certificateArn": "arn:aws:iot:us-east-1:123456972007:cert/d7677b0…SNIP…026d9", "certificatePem": "-----BEGIN CERTIFICATE-----…SNIP…-----END CERTIFICATE-----", "keyPair": { "PublicKey": "-----BEGIN PUBLIC KEY-----…SNIP…-----END PUBLIC KEY-----", "PrivateKey": "-----BEGIN RSA PRIVATE KEY-----…SNIP…-----END RSA PRIVATE KEY-----" }, "certificateId": "d7677b0…SNIP…026d9"}

CreateKeysAndCertificate()

AWS-Generated Keypair

Client Generated Keypair

CSR

Certificate Signing Request

Dear Certificate Authority,I’d really like a certificate for %NAME%, as identified

by the keypair with public key %PUB_KEY%. If you could sign a certificate for me with those parameters, it’d be super spiffy.

Signed (Cryptographically),

- The holder of the private key

Client Generated Keypair

CSR

CreateCertificateFromCSR(CSR)

Actual Commands

$ openssl genrsa –out ThingKeypair.pem 2048Generating RSA private key, 2048 bit long modulus....+++...+++e is 65537 (0x10001)

$ openssl req -new –key ThingKeypair.pem –out Thing.csr-----Country Name (2 letter code) [XX]:USState or Province Name (full name) []:NYLocality Name (eg, city) [Default City]:New YorkOrganization Name (eg, company) [Default Company Ltd]:ACMEOrganizational Unit Name (eg, section) []:MakersCommon Name (eg, your name or your server's hostname) []:John SmithEmail Address []:[email protected]

Actual Commands

$ aws iot create-certificate-from-csr \ --certificate-signing-request file://Thing.csr \ --set-as-active{ "certificateArn": "arn:aws:iot:us-east-1:123456972007:cert/b5a396e…SNIP…400877b", "certificatePem": "-----BEGIN CERTIFICATE-----…SNIP…-----END CERTIFICATE-----", "certificateId": "b5a396e…SNIP…400877b"}

Register your own Certificate Authority

GetVerificationCode()

Register your own Certificate Authority

CSR

RegisterCACertificate(CSR)

Provisioning your own certificates

RegisterCe

rtificate(

Cert)

CSR

Provisioning your own certificates

Just-in-time registration

RegisterCe

rtificate(

Cert)

Just-in-time registration

CONNECT

AWSLambda

NewDevice(Certificate)

AttachPolicy()ActivateCertificate()CreateThing()UpdateShadow()

DISCONNECT

Enhanced Security from Device to Cloud

Private Key Protection – Test & Dev

$ openssl genrsa -out ThingKeypair.pem 2048Generating RSA private key, 2048 bit long modulus......................+++.................................+++e is 65537 (0x10001)

$ ls -l ThingKeypair.pem-rw-rw-r-- 1 ec2-user ec2-user 1679 Sep 25 14:10 ThingKeypair.pem

$ chmod 400 ThingKeypair.pem ; ls -l ThingKeypair.pem-r-------- 1 ec2-user ec2-user 1679 Sep 25 14:10 ThingKeypair.pem

Private Key Protection

SoftwarechrootSELinux

HardwareTPMsSmartcardsOTP FusesFIPS-style hardware

Identity Revocation

$ aws iot list-certificates{ "certificateDescriptions": [ { "certificateArn": "arn:aws:iot:us-east-1:123456972007:cert/d7677b0…SNIP…026d9", "status": "ACTIVE", "certificateId": "d7677b0…SNIP…026d9" "lastModifiedDate": 1443070900.491, "certificatePem": "-----BEGIN CERTIFICATE-----…SNIP…-----END CERTIFICATE-----", "ownedBy": "123456972007", "creationDate": 1443070900.491 } ]}

Identity Revocation

$ aws iot update-certificate --certificate-id "d7677b0…SNIP…026d9" --new-status REVOKED

$ aws iot list-certificates{ "certificateDescriptions": [ { "certificateArn": "arn:aws:iot:us-east-1:123456972007:cert/d7677b0…SNIP…026d9", "status": "REVOKED", "certificateId": "d7677b0…SNIP…026d9" "lastModifiedDate": 1443192020.792, "certificatePem": "-----BEGIN CERTIFICATE-----…SNIP…-----END CERTIFICATE-----", "ownedBy": "123456972007", "creationDate": 1443070900.491 } ]}

Takeaways

• Many provisioning methods

• Each device gets its own certificate

• Use a certificate authority for offline provisioning

Requirements

Secure Communications with ThingsStrong Thing IdentityFine-grained Authorization for:

ThingsPeople

Policy actions

• Connect• Publish• Subscribe• Unsubscribe• Receive

Connect policy

{ "Version":"2012-10-17", "Statement":[ { "Effect":"Allow", "Action":[ "iot:Connect" ], "Resource":"arn:aws:iot:us-east-1:123456972007: client/MY-THING-NAME" } ]}

Connect policy

{ "Version":"2012-10-17", "Statement":[ { "Effect":"Allow", "Action":[ "iot:Connect" ], "Resource":"arn:aws:iot:us-east-1:123456972007: client/MY-THING-NAME_*" } ]} MY-THING-NAME_Application1

MY-THING-NAME_Application2

MY-THING-NAME_Application3

Publish policy

{ "Version":"2012-10-17", "Statement":[ { "Effect":"Allow", "Action":[ "iot:Publish" ], "Resource":"arn:aws:iot:us-east-1:123456972007: topic/$aws/things/MyThing/shadow/update" } ]}

Even finer control

{ "Version":"2012-10-17", "Statement":[ { "Effect":"Allow", "Action":[ "iot:Publish" ], "Resource":"arn:aws:iot:us-east-1:123456972007: topic/$aws/things/MyThing/shadow/update" } ]}

Allows updating the entire shadow

Even finer control

{ "Version":"2012-10-17", "Statement":[ { "Effect":"Allow", "Action":[ "iot:Publish" ], "Resource":"arn:aws:iot:us-east-1:123456972007: topic/actions/MyThing/open" } ]}

Use a different topic

Even finer control

AWS IoT

Direct publishing to shadow

Even finer control

AWS IoT

Use a rule to update specific shadow fields

Takeaways

• Structure topics for permissions

• Make policies as restrictive as possible

• Wildcards can simplify policy management

• Rules can help with fine-grained permissions

Requirements

Secure Communications with ThingsStrong Thing IdentityFine-grained Authorization for:

ThingsPeople

Applications

DynamoDB LambdaKinesis

IAM Role policy{ "Version":"2012-10-17", "Statement":[ { "Effect":"Allow", "Action":[ "iot:Connect" ], "Resource":"*" }, { "Effect":"Allow", "Action":[ "iot:Publish" ], "Resource":["arn:aws:iot:us-east-1:123456972007: topic/$aws/things/MyThing/shadow/update"] }, { "Effect":"Allow", "Action":[ "iot:Subscribe", "iot:Receive" ], "Resource":["arn:aws:iot:us-east-1:123456972007: topicfilter/$aws/things/MyThing/shadow/*" ] } ]}

Mobile

DynamoDB LambdaKinesis

AMAZONCOGNITO

Policy for Cognito with IoTCognito authenticated user identity pool role policy:{ "Effect": "Allow", "Action": [ "iot:Connect", "iot:Publish", "iot:Subscribe", "iot:Receive", "iot:GetThingShadow", "iot:UpdateThingShadow" ], "Resource": "*"}

Specific policy for Joe IoT Cognito user:{ "Effect": "Allow", "Action": "iot:UpdateThingShadow", "Resource": "arn:aws:iot:…:thing/joe-sprinkler123"}

Policy for Cognito with IoTCognito authenticated user identity pool role policy:{ "Effect": "Allow", "Action": [ "iot:Connect", "iot:Publish", "iot:Subscribe", "iot:Receive", "iot:GetThingShadow", "iot:UpdateThingShadow" ], "Resource": "*"}

Specific policy for Joe IoT Cognito user:{ "Effect": "Allow", "Action": "iot:UpdateThingShadow", "Resource": "arn:aws:iot:…:thing/joe-sprinkler123"}

AmazonCognito

Policy for Cognito with IoTCognito authenticated user identity pool role policy:{ "Effect": "Allow", "Action": [ "iot:Connect", "iot:Publish", "iot:Subscribe", "iot:Receive", "iot:GetThingShadow", "iot:UpdateThingShadow" ], "Resource": "*"}

Specific policy for Joe IoT Cognito user:{ "Effect": "Allow", "Action": "iot:UpdateThingShadow", "Resource": "arn:aws:iot:…:thing/joe-sprinkler123"}

AWS IoT

Overall Cognito “pairing” workflow

1. Create a Cognito identity pool2. Customer signs in using mobile app3. Associate their user with their devices4. Create a scope-down policy in IoT for their user5. Attach that policy to their Cognito user in IoT

Overall Cognito “pairing” workflow

1. Create a Cognito identity pool2. Customer signs in using mobile app3. Associate their user with their devices4. Create a scope-down policy in IoT for their user5. Attach that policy to their Cognito user in IoT

Important: These steps apply to authenticated Cognito users only. (NOT to unauthenticated!)

Managing fine-grained permissions

• One user may need permissions to many things• "arn:aws:iot:…:thing/sprinkler123abc"• "arn:aws:iot:…:thing/sprinkler456def"• …

• Listing each is tedious

Best practice: Thing name prefixing

• Prefix thing name with logical owner• sensor123abc -> joe-sensor123abc

• Aspen policy supports wildcards• "arn:aws:iot:…:thing/sensor123abc"• "arn:aws:iot:…:thing/sensor123abc"• "arn:aws:iot:…:thing/sensor456def"• …• "arn:aws:iot:…:thing/joe-*"

Takeaways

• Application access is done through IAM roles/policies

• Cognito enables secure human control over IoT devices

• IoT scope-down policy supports fine-grained control

• Naming conventions simplify policy management

Demo

Creating Certificates - 1-click - CSR

Just In Time Registration

Requirements

Secure Communications with ThingsStrong Thing IdentityFine-grained Authorization for:

ThingsPeople

Thank you!

John Rotach@rotach

AWS IoT: https://aws.amazon.com/iot/

Documentation: https://aws.amazon.com/documentation/iot/

AWS Forums: https://forums.aws.amazon.com/forum.jspa?forumID=210