#MoreCrypto

A small step to make it harder to listen to IP based activity.

V1.8 TLS - oej@edvina.net - slideshare.net/oejⒸ Olle E. Johansson, Stockholm, Sweden 2014.

This work is licensed under

2014-02-09

The problem

We have built an information network that is too easy to monitor. We simply

trusted everyone too much in a naive way.

Sadly, we can’t dothat any more.

#MoreCrypto

The Internet mirrors society

When the Internet was small, there was a select groupof people using it. They felt is was a safe place.

#MoreCrypto

As the Internet grew and reflects more of society,we forgot to harden it. It’s time now.

#MoreCrypto

The engineers are working

The IETF recently decided to focus a lot of energy to add more confidentiality and security in general to the technology

we use every day.

The IETF is the organisation that defined most of the standards we use today to

communicate.

What’s the problem?

#MoreCrypto

Changing the Internetis too hard.

We are not using the security tools we have in the

way they are meant to be used today. In some cases, like e-mail and

IP telephony, most of us do not use any security tools at all.

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How do we change?

The users must require change. Otherwise,very few things happen. It is up to you and me.

#MoreCrypto

What needs to be done?

A lot of changes needs to be done in how we build services, operate them and use them.

More crypto Easy to use authentication

Enhanced privacy Stronger confidentiality

…and much more

#MoreCrypto

TLS is an important tool

TLSTransport

LayerSecurity

TLS provides confidentiality, identity and integrity to Internet communication.

TLS is used in HTTPS:// web pages, but can also be used from applications on a computer as well as a cell

phone.

TLS is based on SSL, that was a provider-specific technology. TLS is maintained by the IETF and is still

being improved.

The second partcovers this!

#MoreCrypto

Start simple.Use connection encryption

wherever possible. Use HTTPS and serve

information over HTTPS

In short:#MoreCrypto

#MoreCrypto

Why?More crypto on the Internet

raise the cost of listening in to our information flows, our

conversations. It does not solve all the issues, we have a lot of work

ahead of us.

Using more TLS is not very complicated and can be used in

most applications today.

#MoreCrypto

Starting points.Enable HTTPS for Facebook, Google and other services

when you can.

Use EFF HTTPS ANYWHERE in your web browser.

If you are a sysadmin, enable TLS and follow new advice on

choice of algorithms.

#MoreCrypto

What does TLS give you?

Browser ServerConfidential path

Other people in the same network (or IT management) can see where you go (server address), but not what you do.

Example:Hotel staff can’t see what you write

or read on Facebook.

#MoreCrypto

What about VPN tunnelling?

Computer Confidential path

Example: Other people in the same network (or IT management)

can see that you are using a VPN, but not what you do.

WebServer

MailServer

VPN = Virtual private network

On the other side of the VPN server your connections become

visible again - unless you are using TLS.

VPN server

Example:Hotel staff can’t see which web

sites you are connecting to.

#MoreCrypto

The work continuesMobileapps Web IP

Telephony E-mail

CloudServices

Internet of things

The Digital home Chat

VideoServices

Require#MoreCrypto!

NEW!

OPPURTUNISTIC SECURITY

Secure network traffic, regardless of what the user says. Do whatever you can to make it harder to listen in.

Introduction to TLS

#MoreCrypto

Transport Layer Security

#MoreCrypto

Identity

Security basics.

Confidentiality

Authorization

Integrity

Non-repudiation

#MoreCrypto

TLS is an important tool

TLSTransport

LayerSecurity

TLS provides confidentiality, identity and integrity to Internet communication.

TLS is used in HTTPS:// web pages, but can also be used from applications on a computer as well as a cell

phone.

TLS is based on SSL, that was a provider-specific technology. TLS is maintained by the IETF and is still

being improved.

#MoreCrypto

Encryption

Using the same key for encryption and decryption

Using the different keys for encryption and decryption

SYMMETRIC ASYMMETRIC

Simple for the CPU, supports streaming data

More computations,easier for data blocks

Using a private and a public key

• TLS use a keypair to set up a secure connection

• Assymetric encryption

• The server sends the public key at connection

• The client challenges the server

• The server responds to the challenge using the server private key

• Now the client knows that the server has the private key that matches the public key

private

TLS Usage• TLS is used for

• authentication of servers and clients

• initiating encryption of a session

• digital signatures on messages to ensure integrity and provide authentication

Authentication Who are you? Prove it!

Encryption Providing confidentiality

Integrity Making sure that the receiver get what the

sender sent

Adding a certificate to the mix

• A certificate is nothing more complicated than a passport or an ID card

• It contains the public key and some administrative data

• And is signed (electronically) by someone you might trust ... or not.

• This is part of the complex structure called PKI, which you might want or just disregard

• A PKI is not needed to get encryption for the signalling path!

• You can however use a PKI to only set up connections that you trust

The X.509v3 certificate• An X.509 certificate is the standardised way to

bind a public key to an identity • The certificate is issued by a

Certification Authority (CA)

• The most important component of the PKI?

• An X.509 certificate is an electronic document with a specific layout

!

• Standard: documented in IETF PKIX RFC:s

Version

Serial number

Issuer identity

Validity period

User identity

Public key

Extension fields

X509.v3contents

• Version number

• Certificate serial numberUsed for validation

• Identity of the issuer • Validity period • Identity of the public key owner • Public key • Extension fields • A digital signature, created by the issuer

InternetExplorer

CertificateManager

Example: SIP certificates• SubjectAltName contains a list of

identities that are valid for this certificate

• RFC 5922 outlines a SIP event package to distribute and manage certificates

• This is based on the Authentication Service in SIP identity (RFC 4474)

• The domain cert is used to sign the NOTIFY payload

TLS is more than the world wide web!

x.509 cert for SIPCertificate: Data: Version: 3 (0x2) Serial Number: 01:08:00:79:00:15:00:43 Signature Algorithm: sha1WithRSAEncryption Issuer: C=US, ST=California, L=San Jose, O=sipit, OU=Sipit Test Certificate Authority Validity Not Before: Sep 16 17:17:00 2009 GMT Not After : Sep 15 17:17:00 2012 GMT Subject: C=US, ST=California, L=San Jose, O=sipit, CN=tls6.test.sipit.net Subject Public Key Info: Public Key Algorithm: rsaEncryption RSA Public Key: (2048 bit) Modulus (2048 bit): 00:a7:96:65:6e:b6:ba:3a:48:a1:bd:a3:ae:21:dc: a8:92:97:3c:43:ea:24:e6:9f:93:2f:61:7e:d3:2d: 30:1e:21:42:b9:d6:59:87:f1:b1:f8:c8:39:8e:43: 64:9a:31:2c:18:3d:cd:d8:03:64:bb:14:38:44:05: 20:30:d8:e1:db:a7:4d:c3:47:a2:49:73:d1:10:ed: 2f:cf:74:26:57:91:64:af:b0:f2:5d:3f:88:9f:df: 65:6c:ba:65:3f:66:99:52:6b:20:d2:0e:e3:65:18: b1:8e:3d:ca:f2:4a:45:c5:4d:85:ef:82:54:f8:54: 54:db:96:90:9b:c5:1b:2a:1e:60:3c:43:71:55:60: 30:93:8f:fd:d8:d9:3d:a1:32:e3:56:4b:e2:73:b6: cc:18:93:8a:d8:8b:68:81:c7:fd:cd:d5:dc:4c:a2: 86:61:9f:ad:d0:b1:d3:3c:4c:6c:07:54:b2:43:b4: a7:0a:0a:f2:e3:6d:12:43:16:70:63:c9:e9:1a:78: 66:9d:ee:30:94:7b:ab:f2:e9:67:4a:66:6d:8c:ed: a8:a4:98:51:77:0b:a7:60:55:73:85:87:4a:57:6b: 24:fe:27:00:02:79:70:da:5a:45:ad:aa:3d:d5:40: 5b:5c:85:63:93:56:af:c7:e8:e3:b6:1a:25:b6:a2: 2d:37 Exponent: 65537 (0x10001) X509v3 extensions: X509v3 Subject Alternative Name: DNS:test.sipit.net, DNS:tls6.test.sipit.net, URI:sip:tls6.test.sipit.net X509v3 Basic Constraints: CA:FALSE X509v3 Subject Key Identifier: 27:F7:A9:96:F5:B2:8F:0B:5E:A9:C7:F5:0F:AC:3D:AB:3D:8D:F0:30 Signature Algorithm: sha1WithRSAEncryption 1a:fe:1f:af:86:99:82:e5:14:97:8d:64:9a:d1:5c:ea:6c:96: f5:c6:0c:7d:20:5f:4e:70:05:24:3a:de:b5:b9:cf:66:8d:4c: 74:d5:6a:a9:52:74:17:bc:b4:79:a0:58:32:78:a9:70:7c:6a: 15:ac:07:29:77:13:06:55:53:3f:0b:4c:3d:da:55:6e:ad:74: 56:01:55:c8:4c:19:8d:06:0b:f3:4c:04:d5:9a:6f:44:ad:7a: fd:3b:aa:e8:4b:84:6e:f1:c4:34:f4:a0:6a:f6:81:ae:74:b4: 46:6e:b9:2f:a6:59:f1:02:e9:58:7c:a1:8d:08:31:2b:39:ee: eb:7e

Subject: C=US, ST=California, L=San Jose, O=sipit, CN=tls6.test.sipit.net

X509v3 Subject Alternative Name: DNS:test.sipit.net, DNS:tls6.test.sipit.net, URI:sip:tls6.test.sipit.net

Notice the URI in the certificate!

Process for a serverGenerate

KeysPack public key

in CSR

Send CSRto CA

CA validateprocess

CA issues Certificate

Install certin server withprivate key

Client connectionOpen TCPconnection

Server sendscertificate

Clientchallenge server

Server answerschallenge

Client validatescertificate

Server can issue cert request

Client and server produce session key

Symmetric encryption starts

Issues

Certificate can validate correctly with the CA store, but still be the

wrong certificate.

Certificate private key can be copied and certificate

revocated.

DNS was spoofed, so we reached the wrong service

Something new and even more scary than Heartbleed.

Protocol specifics

• Given a protocol request - how do we match the request address to a certificate

• SIP Uri, E-mail address, HTTPS uri

#MoreCrypto

TLS and SSLSSL v1.0 - 2.0

Created by Netscape Communications

Deemed insecure.

SSL v3.0 Last version. No support for

extensions and not for modern crypto algorithms. Deemed

insecure.

TLS 1.x Open standard defined by the IETF. Keeps being updated.

It’s time to try to stop using SSL.

Man in the middle

• How do we prevent and discover TLS proxys?

• Quite commonly used

Client ServerMITM

#MoreCrypto

Certificate FingerprintingCertificates have a fingerprint, a checksum of the cert and key.

Embed last, current and next certificate fingerprint in the code

Verify that you are talking with the expected server.

TLS verification may work with a bad server cert too.

Client ServerMITM

Client Server

#MoreCrypto

Trust on first useSave certificate fingerprint on

first connection

If another certificate shows up, warn the user

Don’t block, the first connection could be bad

Certificates gets updatesso save expiry time and

accept new.

Client ServerMITM

Client Server

#MoreCrypto

DANE - using DNSsecSave cert in DNS, signed by

DNSsec

If another certificate shows up, do not continue. Disconnect.

Certificates that expired or was revoked has no NS records

Client ServerMITM

Client Server

Client DNSDNS query

TLS connection

User specifics

• Which CAs do we trust?

• How do we check validity of certificate, even if we trust the CA?

• Do we have time for validation?

New solutions

• Anchoring the certificate in DNS

• Validating the certificate in DNS

• No certificate - bare keys

• Oppurtunistic Security with TLS

DNSsec

Advice:

• Use encrypted communication by default

• Authenticated sessions are better than non-authenticated

• If you really need confidentiality, check ciphers and checksum algorithms

#MoreCrypto

Heartbleed

• Programming error in OpenSSL

• OpenSSL is used in too many places

• Opened up for private key distribution and a lot of other in-memory data.

Security is a process

• There will be other issues with TLS libraries, protocols and implementations

• Having these is better than having no security, integrity, privacy or confidentiality

#MoreCrypto

To-do listSECURITY:

Always build secure platforms. Encrypt all communication.1.IPv6:

Integrate IPv6 in every single project.2.DNSsec:

Sign your DNS data. DNS is the foundation for all of Internet.3.

The way forward:

#MoreCrypto

#MoreCrypto

More informationhttp://www.internetsociety.org/deploy360/tls/

https://bettercrypto.org

http://tools.ietf.org/html/rfc7258 - Internet is under attack.

Join us!

• IETF peerpass mailing list, UTA working group and more.

• Hashtag #MoreCrypto

• http://internetsociety.org

Feedback?• Feedback and suggestions for improvements to this presentation is

more than welcome! Send to oej@edvina.net!

• Feel free to use this presentation yourself - Notice the Creative commons license on this presentation!

• Please tell me if you use it! It’s always fun to know.

#MoreCrypto

Author: oej@edvina.net - slideshare.net/oejⒸ Olle E. Johansson, Stockholm, Sweden 2014.

This work is licensed under

Olle E. Johansson