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SIPNOC 2014 - Is It Time For TLS for SIP?

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Is it time for TLS for SIP-based Voice over IP(VoIP)? At SIPNOC 2014 on June 10, 2014, I spoke about how to secure VOIP communications using TLS and what are both the challenges and benefits.

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SIPNOC 2014 - Is It Time For TLS for SIP?

  1. 1. www.internetsociety.org/deploy360/ Is It Time For TLS For SIP? SIP Network Operators Conference (SIPNOC) 2014 Herndon, VA, USA June 10, 2014 Dan York Internet Society
  2. 2. www.internetsociety.org/deploy360/ Dan York and VoIP/SIP Mitel Networks, 2001 – 2007 •  Chair, product security team •  Product manager, SIP software, teleworking Voxeo, 2007-2011 •  Cloud-based SIP operations Blue Box: The VoIP Security Podcast, 2005-2008 - www.blueboxpodcast.com Disruptive Telephony , 2006-present – www.disruptivetelephony.com Author, Seven Deadliest Unified Communications Attacks, 2010 •  www.7ducattacks.com VoIP Security Alliance (VOIPSA), 2005-present •  www.voipsa.org Internet Engineering Task Force (IETF), 2006-present •  Active in Real-time Applications and Infrastructure (RAI) working groups Joined Internet Society in September 2011
  3. 3. www.internetsociety.org/deploy360/ About the Deploy360 Programme The Challenge: –  The IETF creates protocols based on open standards, but some are not widely known or deployed –  People seeking to implement these protocols are confused by a lack of clear, concise deployment information The Deploy360 Solution: –  Provide hands-on information on IPv6, DNSSEC, BGP and TLS to advance real-world deployment –  Work with first adopters to collect and create technical resources and distribute these resources to fast following networks
  4. 4. www.internetsociety.org/deploy360/ Internet Society Deploy360 Programme www.internetsociety.org/deploy360/ IPv6, DNSSEC, Securing BGP, TLS for Applications knowledge base including tutorials, case studies, training resources, etc. Content specific to: –  Network Operators –  Developers –  Content Providers –  Consumer Electronics Manufacturers –  Enterprise Customers Blog posts ION conferences, speaking, social media
  5. 5. www.internetsociety.org/deploy360/ Time For TLS? 6/10/14
  6. 6. www.internetsociety.org/deploy360/ TLS = Transport Layer Security TLS 1.0 ≈ SSL 3.0 RFC 2246 1999 TLS 1.1 RFC 4346 2006 TLS 1.2 RFC 5246 2008 TLS 1.3 draft-ietf-tls-rfc5246-bis TLS – The Protocol Formerly Known As "SSL"
  7. 7. www.internetsociety.org/deploy360/ How many of you currently use TLS in SIP-based communications?
  8. 8. www.internetsociety.org/deploy360/ Why not?
  9. 9. www.internetsociety.org/deploy360/ Reasons for not using TLS with SIP •  Debugging •  Network Monitoring •  Performance •  Lack of Device/Application Support •  Cost •  Complexity •  No customer demand 6/10/14
  10. 10. www.internetsociety.org/deploy360/ Why am I here at SIPNOC?
  11. 11. www.internetsociety.org/deploy360/ Snowden
  12. 12. www.internetsociety.org/deploy360/ Tinfoil Hats 6/10/14 https://www.flickr.com/photos/ripper/273262947
  13. 13. www.internetsociety.org/deploy360/ Tinfoil Hats Were Wrong – It Was Worse 6/10/14 https://www.flickr.com/photos/ncreedplayer/3210543345/
  14. 14. www.internetsociety.org/deploy360/ RFC 7280 - Pervasive Monitoring Is an Attack "The IETF community's technical assessment is that pervasive monitoring (PM) is an attack on the privacy of Internet users and organisations. The IETF community has expressed strong agreement that PM is an attack that needs to be mitigated where possible, via the design of protocols that make PM significantly more expensive or infeasible." •  http://tools.ietf.org/html/rfc7258 - May 2014 6/10/14
  15. 15. www.internetsociety.org/deploy360/ Not Waiting For New Standards
  16. 16. www.internetsociety.org/deploy360/ XMPP (Jabber) Community •  As of May 19, 2014, over 70 public XMPP operators and developers have agreed to ONLY accept TLS-encrypted connections •  https://github.com/stpeter/manifesto •  http://blog.prosody.im/mandatory-encryption-on-xmpp- starts-today/ •  https://xmpp.net/ 6/10/14
  17. 17. www.internetsociety.org/deploy360/ What can we do as the SIP operator community to promote greater TLS usage?
  18. 18. www.internetsociety.org/deploy360/ Can we create our own manifesto?
  19. 19. www.internetsociety.org/deploy360/ A few caveats…
  20. 20. www.internetsociety.org/deploy360/ TLS Only Solves Part Of Privacy Protection 6/10/14
  21. 21. www.internetsociety.org/deploy360/ SRTP Is Needed For Media Protection 6/10/14
  22. 22. www.internetsociety.org/deploy360/ Our Simple Picture… 6/10/14
  23. 23. www.internetsociety.org/deploy360/ … Isn't So Simple 6/10/14
  24. 24. www.internetsociety.org/deploy360/ TLS Is Only Hop-by-hop, Not End-to-end 6/10/14
  25. 25. www.internetsociety.org/deploy360/ And "Unified Communications" Isn't Unified… 6/10/14 Physical WiringIP Network IP-PBX Voicemail PSTN Gateways Mobile Devices IM Networks Web Servers Email Servers Desktop PCs Operating Systems Firewalls Internet Directory Servers VoIP CRM Systems Social Networks Database Servers Application Servers Session Border Controllers
  26. 26. www.internetsociety.org/deploy360/ But…
  27. 27. www.internetsociety.org/deploy360/ We Have The Standards… A partial list: 6/10/14 RFC 5280 X.509 Certificates and CRLs RFC 5922 Domain Certificates in SIP RFC 5923 Connection Re-use in SIP RFC 6072 Certificate Management System for SIP RFC 3711 Secure Real-time Transport Protocol (SRTP) RFC 4568 SDP for SRTP RFC 5763 Using SRTP with DTLS RFC 6347 Datagram TLS (DTLS – "TLS for UDP")
  28. 28. www.internetsociety.org/deploy360/ We Have A Specification… SIPconnect 1.1 requires TLS www.sipforum.org/sipconnect Caveat: Focused on SIP PBX to Service Provider connection 6/10/14
  29. 29. www.internetsociety.org/deploy360/ We Have The Tools… TLS support can be found in most: •  IP-PBXs •  Softphones •  IP phones •  SIP applications (But often simply not enabled) 6/10/14
  30. 30. www.internetsociety.org/deploy360/ What can we do as the SIP operator community to promote greater TLS usage?
  31. 31. www.internetsociety.org/deploy360/ One more caveat: Can we trust the certificates?
  32. 32. www.internetsociety.org/deploy360/ 1,500-ish CAs Any of whom can sign for any domain
  33. 33. www.internetsociety.org/deploy360/ A Quick Overview of DANE Can it add more trust to TLS-based communication? 6/10/14
  34. 34. www.internetsociety.org/deploy360/ The Typical TLS (SSL) Web Interaction Web Server Web Browser https://example.com/ TLS-encrypted web page DNS Resolver example.com? 10.1.1.1231 2 5 6 DNS Svr example.com DNS Svr .com DNS Svr root 3 10.1.1.123 4
  35. 35. www.internetsociety.org/deploy360/ The Typical TLS (SSL) Web Interaction Web Server Web Browser https://example.com/ TLS-encrypted web page DNS Resolver 10.1.1.1231 2 5 6 DNS Svr example.com DNS Svr .com DNS Svr root 3 10.1.1.123 4 Is this encrypted with the CORRECT certificate? example.com?
  36. 36. www.internetsociety.org/deploy360/ Problems? Web Server Web Browser https://www.example.com/ TLS-encrypted web page with CORRECT certificate DNS Server www.example.com? 1.2.3.4 1 2 Attacker (or firewall) https://www.example.com/ TLS-encrypted web page with NEW certificate (re-signed by attacker)Log files or other servers
  37. 37. www.internetsociety.org/deploy360/ DNS-Based Authentication of Named Entities (DANE) •  Q: How do you know if the TLS (SSL) certificate is the correct one the site wants you to use? •  A: Store the certificate (or fingerprint) in DNS (new TLSA record) and sign them with DNSSEC. A browser that understand DNSSEC and DANE will then know when the required certificate is NOT being used. Certificate stored in DNS is controlled by the domain name holder. It could be a certificate signed by a CA – or a self- signed certificate.
  38. 38. www.internetsociety.org/deploy360/ DANE Web Server Web Browser w/DANE https://example.com/ TLS-encrypted web page with CORRECT certificate DNS Server 10.1.1.123 DNSKEY RRSIGs TLSA 1 2 Attacker (or firewall) https://example.com/ TLS-encrypted web page with NEW certificate (re-signed by attacker) Log files or other servers DANE-equipped browser compares TLS certificate with what DNS / DNSSEC says it should be. example.com?
  39. 39. www.internetsociety.org/deploy360/ The DANE Protocol •  DANE defined in RFC 6698 •  https://tools.ietf.org/html/rfc6698 •  TLSA record contains either a certificate or the public key of a certificate •  Four modes of certificate usage: •  0 – "CA constraint" – limits which CA can be used for certificates •  1 – "service certificate constraint" – specifies exact CA-signed certificate •  2 – "trust anchor assertion" – allows use of a new trust anchor (such as a CA not included in the browser list) •  3 – "domain-issued certificate" – use of self-signed certificate 6/10/14
  40. 40. www.internetsociety.org/deploy360/ DANE – Not Just For The Web •  DANE defines protocol for storing TLS certificates in DNS •  Securing Web transactions is the obvious use case •  Other uses also possible: •  Email via S/MIME •  VoIP •  Jabber/XMPP •  PGP •  ? 6/10/14
  41. 41. www.internetsociety.org/deploy360/ DANE Resources DANE and SIP: •  http://tools.ietf.org/html/draft-johansson-dispatch-dane-sip DANE and email: •  http://tools.ietf.org/html/draft-ietf-dane-smtp •  http://tools.ietf.org/html/draft-ietf-dane-smime DANE Operational Guidance: •  http://tools.ietf.org/html/draft-dukhovni-dane-ops Other uses: •  http://tools.ietf.org/html/draft-wouters-dane-openpgp •  http://tools.ietf.org/html/draft-wouters-dane-otrfp
  42. 42. www.internetsociety.org/deploy360/ DANE Resources DANE Overview and Resources: •  http://www.internetsociety.org/deploy360/resources/dane/ IETF Journal article explaining DANE: •  http://bit.ly/dane-dnssec RFC 6394 - DANE Use Cases: •  http://tools.ietf.org/html/rfc6394 RFC 6698 – DANE Protocol: •  http://tools.ietf.org/html/rfc6698
  43. 43. www.internetsociety.org/deploy360/ Next Steps
  44. 44. www.internetsociety.org/deploy360/ What can we do as the SIP operator community to promote greater TLS usage?
  45. 45. www.internetsociety.org/deploy360/ Resources Deploy360 Programme: •  http://www.internetsociety.org/deploy360/tls/ Olle Johansson: •  http://www.slideshare.net/oej/presentations •  http://www.slideshare.net/oej/morecrypto-sip
  46. 46. www.internetsociety.org/deploy360/ Three Requests For Network Operators 1.  Require TLS for all SIP connections where possible 2.  Support industry efforts to increase TLS usage 3.  Help promote support of DANE protocol •  Allow usage of TLSA record. Let vendors and others know you want to use DANE. Help raise awareness of how DANE and DNSSEC can make the Internet more secure.
  47. 47. www.internetsociety.org/deploy360/ york@isoc.org www.internetsociety.org/deploy360/ Dan York, CISSP Senior Content Strategist, Internet Society Thank You!
  48. 48. www.internetsociety.org/deploy360/ Background: A Quick Overview of DNSSEC 6/10/14
  49. 49. www.internetsociety.org/deploy360/ A Normal DNS Interaction Web Server Web Browser https://example.com/ web page DNS Resolver 10.1.1.123 1 25 6 DNS Svr example.com DNS Svr .com DNS Svr root 3 10.1.1.123 4 example.com NS .com NS example.com?
  50. 50. www.internetsociety.org/deploy360/ Attacking DNS Web Server Web Browser https://example.com/ web page DNS Resolver 10.1.1.123 1 25 6 DNS Svr example.com DNS Svr .com DNS Svr root 3 192.168.2.2 4 Attacking DNS Svr example.com 192.168.2.2 example.com NS .com NS example.com?
  51. 51. www.internetsociety.org/deploy360/ A Poisoned Cache Web Server Web Browser https://example.com/ web page DNS Resolver1 2 3 4 192.168.2.2 Resolver cache now has wrong data: example.com 192.168.2.2 This stays in the cache until the Time-To-Live (TTL) expires! example.com?
  52. 52. www.internetsociety.org/deploy360/ A DNSSEC Interaction Web Server Web Browser https://example.com/ web page DNS Resolver 10.1.1.123 DNSKEY RRSIGs 1 25 6 DNS Svr example.com DNS Svr .com DNS Svr root 3 10.1.1.123 4 example.com NS DS .com NS DS example.com?
  53. 53. www.internetsociety.org/deploy360/ Attempting to Spoof DNS Web Server Web Browser https://example.com/ web page DNS Resolver 10.1.1.123 DNSKEY RRSIGs 1 25 6 DNS Svr example.com DNS Svr .com DNS Svr root 3 SERVFAIL 4 Attacking DNS Svr example.com 192.168.2.2 DNSKEY RRSIGs example.com NS DS .com NS DS example.com?
  54. 54. www.internetsociety.org/deploy360/ The Two Parts of DNSSEC Signing Validating ISPs Enterprises Applications DNS Hosting Registrars Registries
  55. 55. www.internetsociety.org/deploy360/ DNSSEC Signing - The Individual Steps Registry Registrar DNS Hosting Provider Domain Name Registrant •  Signs TLD •  Accepts DS records •  Publishes/signs records •  Accepts DS records •  Sends DS to registry •  Provides UI for mgmt •  Signs zones •  Publishes all records •  Provides UI for mgmt •  Enables DNSSEC (unless automatic)
  56. 56. www.internetsociety.org/deploy360/ DNSSEC Signing - The Players Registries Registrars DNS Hosting Providers Domain Name Registrants Registrar also provides DNS hosting services
  57. 57. www.internetsociety.org/deploy360/ DNSSEC Signing - The Players Registries Registrars DNS Hosting Providers Domain Name Registrants Registrant hosts own DNS
  58. 58. www.internetsociety.org/deploy360/ Signing Can Be Simple
  59. 59. www.internetsociety.org/deploy360/ DNSSEC Resources Deploy360 Programme: •  www.internetsociety.org/deploy360/dnssec/ DNSSEC Deployment Initiative: •  www.dnssec-deployment.org/ DNSSEC Tools: •  www.dnssec-tools.org/ DNSSEC and VoIP: •  www.internetsociety.org/deploy360/resources/dnssec-voip/
  60. 60. www.internetsociety.org/deploy360/ Three Requests For Network Operators (ISPs) 1.  Deploy DNSSEC-validating DNS resolvers 2.  Sign your own domains where possible 3.  Help promote support of DANE protocol •  Allow usage of TLSA record. Let browser vendors and others know you want to use DANE. Help raise awareness of how DANE and DNSSEC can make the Internet more secure.
  61. 61. www.internetsociety.org/deploy360/ 3 More Requests For SIP Network Operators 1.  Think about how and where DNSSEC and DANE could be potentially used 2.  Experiment with the early implementations like Jitsi and Kamailio 3.  Share the ideas… •  Directly with me ( york@isoc.org ) or via email lists, online forums, etc. •  http://www.internetsociety.org/deploy360/dnssec/community/ (or let's make a new place for DNSSEC and VoIP)
  62. 62. www.internetsociety.org/deploy360/ Helping Accelerate DNSSEC Deployment https://elists.isoc.org/mailman/listinfo/dnssec-coord Public mailing list, “dnssec-coord”, available and open to all: Focus is on better coordinating promotion / advocacy / marketing activities related to DNSSEC deployment. Monthly conference calls and informal meetings at ICANN and IETF events.

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