Understanding HTTPS and TLS

Google, Firefox, and the IETF are currently engaged in major initiatives to convert the web to be secure by default. Page ranking, new browser APIs, and HTTP/2 are all pushing websites to require HTTPS. An HTTPS only web is imminent. Unfortunately, according to SSL Pulse, 75% of the top 1 million websites that use HTTPS are not actually secure because of misconfiguration. Do you know how to configure HTTPS properly? In my talk, I will discuss the key aspects of HTTPS to empower developers to deploy truly secure HTTPS sites.

Transcript

1. Understanding HTTPS and TLS Zack Tollman @tollmanz
3. “Pervasive monitoring is a technical attack that should be mitigated in the design of IETF protocols, where possible.” — IETF https://tools.ietf.org/html/rfc7258
4. “Today we are announcing our intent to phase out non-secure HTTP” — Richard Barnes, Firefox Security Lead https://blog.mozilla.org/security/2015/04/30/deprecating-non-secure-http/
5. HTTP/2 is TLS only in Chrome, Firefox, Opera, IE/Edge, and Safari https://wiki.mozilla.org/Networking/http2
6. Now Later Less HTTPS More HTTPS
7. HTTPS knowledge is now essential
8. We are bad at HTTPS
9. 58% of sites are not secure https://www.trustworthyinternet.org/ssl-pulse/
10. “misconfiguration errors are undermining the potential security” — Kranch & Bonneau (2015) http://www.internetsociety.org/sites/default/files/01_4_0.pdf
11. “industry-wide configuration problem with the deployment of DHE key exchange” — Huang, Adhikarla, Boneh, & Jackson (2014) http://www.w2spconf.com/2014/papers/TLS.pdf
12. Why?
13. Unless you are a cryptographer, this stuff is hard
14. Copying and pasting is easy
15. Knowing what you are doing is hard
16. TLS Basics
17. Transport Layer Security
18. SSL v2 SSL v3 TLS v1 TLS v1.1 TLS v1.2 1995 1996 1999 2006 2008
19. TCP Transport Layer Security HTTP
20. Provides authentication, encryption, integrity, and key exchange
21. Authentication
22. Is the server the intended server?
23. Integrity
24. Is the message received the message sent?
25. Encryption
26. Converts plaintext to ciphertext
27. j b e q c e r f f
28. j b e q c e r f f w o r d p r e s s
29. A B C D E F N O P Q R S +13
30. Letter + 13 = Cipher Letter
31. Substitution Cipher Caesar Cipher
32. Key is 13
33. Key owners can encrypt and decrypt
34. Key Exchange
35. How do we establish an encryption key for 2 unknown parties over an insecure connection?
36. By Alessandro Nassiri - Museo della Scienza e della Tecnologia "Leonardo da Vinci", CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=47910919
37. Diffie-Hellman-Merkle key exchange
38. p = 23 g = 5 https://github.com/tollmanz/diffie-hellman-key-exchange-demo Demo
39. If anything goes wrong, make a joke about bad wifi
40. Compromise of any of these, compromises the whole system
41. Cipher Suites
42. Combination of algorithms for authentication, integrity, encryption, and key exchange
43. ssl_protocols TLSv1 TLSv1.1 TLSv1.2; ssl_certificate /path/to/public.crt; ssl_certificate_key /path/to/private.key; ssl_ciphers ECDHE-RSA-AES128-GCM- SHA256:ECDHE-ECDSA-AES128-GCM- SHA256:ECDHE-RSA-AES256-GCM-SHA384:ECDHE- ECDSA-AES256-GCM-SHA384…; ssl_prefer_server_ciphers on; https://github.com/igrigorik/istlsfastyet.com/blob/master/nginx/includes/ssl.conf
44. ECDHE-RSA-AES128-GCM-SHA256
45. ECDHE-RSA-AES128-GCM-SHA256 Key Exchange
46. ECDHE-RSA-AES128-GCM-SHA256 Certificate signing algorithm (Authentication)
47. ECDHE-RSA-AES128-GCM-SHA256 Cipher (Encryption)
48. ECDHE-RSA-AES128-GCM-SHA256 Message authentication code (Integrity)
49. ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES128- GCM-SHA256:ECDHE-RSA-AES256-GCM-SHA384:ECDHE- ECDSA-AES256-GCM-SHA384:DHE-RSA-AES128-GCM- SHA256:DHE-DSS-AES128-GCM-SHA256:kEDH +AESGCM:ECDHE-RSA-AES128-SHA256:ECDHE-ECDSA- AES128-SHA256:ECDHE-RSA-AES128-SHA:ECDHE-ECDSA- AES128-SHA:ECDHE-RSA-AES256-SHA384:ECDHE-ECDSA- AES256-SHA384:ECDHE-RSA-AES256-SHA:ECDHE-ECDSA- AES256-SHA:DHE-RSA-AES128-SHA256:DHE-RSA-AES128- SHA:DHE-DSS-AES128-SHA256:DHE-RSA-AES256- SHA256:DHE-DSS-AES256-SHA:DHE-RSA-AES256- SHA:AES128-GCM-SHA256:AES256-GCM-SHA384:AES128- SHA256:AES256-SHA256:AES128-SHA:AES256- SHA:AES:CAMELLIA:DES-CBC3-SHA:!aNULL:!eNULL:! EXPORT:!DES:!RC4:!MD5:!PSK:!aECDH:!EDH-DSS-DES- CBC3-SHA:!EDH-RSA-DES-CBC3-SHA:!KRB5-DES-CBC3- SHA
50. ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES128- GCM-SHA256:ECDHE-RSA-AES256-GCM-SHA384:ECDHE- ECDSA-AES256-GCM-SHA384:DHE-RSA-AES128-GCM- SHA256:DHE-DSS-AES128-GCM-SHA256:kEDH +AESGCM:ECDHE-RSA-AES128-SHA256:ECDHE-ECDSA- AES128-SHA256:ECDHE-RSA-AES128-SHA:ECDHE-ECDSA- AES128-SHA:ECDHE-RSA-AES256-SHA384:ECDHE-ECDSA- AES256-SHA384:ECDHE-RSA-AES256-SHA:ECDHE-ECDSA- AES256-SHA:DHE-RSA-AES128-SHA256:DHE-RSA-AES128- SHA:DHE-DSS-AES128-SHA256:DHE-RSA-AES256- SHA256:DHE-DSS-AES256-SHA:DHE-RSA-AES256- SHA:AES128-GCM-SHA256:AES256-GCM-SHA384:AES128- SHA256:AES256-SHA256:AES128-SHA:AES256- SHA:AES:CAMELLIA:DES-CBC3-SHA:!aNULL:!eNULL:! EXPORT:!DES:!RC4:!MD5:!PSK:!aECDH:!EDH-DSS-DES- CBC3-SHA:!EDH-RSA-DES-CBC3-SHA:!KRB5-DES-CBC3- SHA
51. ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES128- GCM-SHA256:ECDHE-RSA-AES256-GCM-SHA384:ECDHE- ECDSA-AES256-GCM-SHA384:DHE-RSA-AES128-GCM- SHA256:DHE-DSS-AES128-GCM-SHA256:kEDH +AESGCM:ECDHE-RSA-AES128-SHA256:ECDHE-ECDSA- AES128-SHA256:ECDHE-RSA-AES128-SHA:ECDHE-ECDSA- AES128-SHA:ECDHE-RSA-AES256-SHA384:ECDHE-ECDSA- AES256-SHA384:ECDHE-RSA-AES256-SHA:ECDHE-ECDSA- AES256-SHA:DHE-RSA-AES128-SHA256:DHE-RSA-AES128- SHA:DHE-DSS-AES128-SHA256:DHE-RSA-AES256- SHA256:DHE-DSS-AES256-SHA:DHE-RSA-AES256- SHA:AES128-GCM-SHA256:AES256-GCM-SHA384:AES128- SHA256:AES256-SHA256:AES128-SHA:AES256- SHA:AES:CAMELLIA:DES-CBC3-SHA:!aNULL:!eNULL:! EXPORT:!DES:!RC4:!MD5:!PSK:!aECDH:!EDH-DSS-DES- CBC3-SHA:!EDH-RSA-DES-CBC3-SHA:!KRB5-DES-CBC3- SHA
54. What?
55. Use Mozilla’s guide https://wiki.mozilla.org/Security/Server_Side_TLS
56. The Code Book Simon Singh High Performance Browser Networking (TLS Chapter) Ilya Grigorik Bulletproof SSL and TLS Ivan Ristic SSL and TLS: Designing and Building Secure Systems Eric Rescorla
57. https://speakerdeck.com/ tollmanz/understanding- https-and-tls @tollmanz