The first few milliseconds of HTTPS

Transcript

1. The first 200 milliseconds of HTTPS 1 Joshua Thijssen jaytaph
3. ➡ What’s happening in the first 200+ milliseconds in a initial HTTPS connection. 2
4. ➡ What’s happening in the first 200+ milliseconds in a initial HTTPS connection. ➡ Give tips and hints on hardening your setup. 2
5. ➡ What’s happening in the first 200+ milliseconds in a initial HTTPS connection. ➡ Give tips and hints on hardening your setup. ➡ Give you insights in new and upcoming technologies. 2
6. ➡ What’s happening in the first 200+ milliseconds in a initial HTTPS connection. ➡ Give tips and hints on hardening your setup. ➡ Give you insights in new and upcoming technologies. ➡ Show you things to you (probably) didn’t knew. 2
7. This talk is inspired by a blogpost from Jeff Moser http://www.moserware.com/2009/06/first-few-milliseconds-of-https.html Unknown fact! 3
8. HTTPS == HTTP on top of TLS 4
9. Transport Layer Security (TLS) 5
10. Secure Socket Layer (SSL) 6 A short and scary history
11. then now 7
12. then now SSL 1.0 Vaporware 1994 7
13. then now feb 1995 SSL 2.0 Not-so-secure-socket-layer SSL 1.0 Vaporware 1994 7
14. then now feb 1995 SSL 2.0 Not-so-secure-socket-layer jun 1996 SSL 3.0 Something stable! SSL 1.0 Vaporware 1994 7
15. then now feb 1995 SSL 2.0 Not-so-secure-socket-layer jun 1996 SSL 3.0 Something stable! jan 1999 TLS 1.0 SSL 3.1 SSL 1.0 Vaporware 1994 7
16. then now feb 1995 SSL 2.0 Not-so-secure-socket-layer jun 1996 SSL 3.0 Something stable! jan 1999 TLS 1.0 SSL 3.1 apr 2006 TLS 1.1 SSL 1.0 Vaporware 1994 7
17. then now feb 1995 SSL 2.0 Not-so-secure-socket-layer jun 1996 SSL 3.0 Something stable! jan 1999 TLS 1.0 SSL 3.1 apr 2006 TLS 1.1 TLS 1.2 aug 2008 SSL 1.0 Vaporware 1994 7
18. https://www.trustworthyinternet.org/ssl-pulse/ 25,7% 99,6% 99,3% 18,2% 20,7% SSL 2.0 SSL 3.0 TLS 1.0 TLS 1.1 TLS 1.2 8 November 2013
19. https://www.trustworthyinternet.org/ssl-pulse/ 25,7% 99,6% 99,3% 18,2% 20,7% SSL 2.0 SSL 3.0 TLS 1.0 TLS 1.1 TLS 1.2 8 20,5% 98,5% 99,3% 38,4% 40,8% SSL 2.0 SSL 3.0 TLS 1.0 TLS 1.1 TLS 1.2 November 2013 Aug 2014
20. RFC 5246 (TLS v1.2) 9
21. 10 Record Layer
22. 10 Record Layer Type Version Length
23. 10 Record Layer Type Version Length Protocol
24. 10 Record Layer Type Version Length Protocol Protocol Protocol
25. 10 Record Layer Type Version Length Protocol Protocol Protocol Record Layer Type Version Length Protocol
26. ➡ Handshake protocol records ➡ Setup communication ➡ Change Cipher Spec protocol records ➡ Change communication ➡ Alert protocol records ➡ Errors ➡ Application Data protocol records ➡ Actual data transfers 11
27. 12 https://github.com/vincentbernat/rfc5077/blob/master/ssl-handshake.svg
28. Attention: (live) wiresharking up ahead 13
31. Generating randomness is HARD 16
32. entropy (uncertainty) 17
33. TIME is NOT random thus not a very good entropy source 18
34. PHP is bad when it comes to entropy 19 Unknown fact!
36. openssl_pseudo_random_bytes() 20
37. openssl_pseudo_random_bytes() read from /dev/(u)random 20
38. openssl_pseudo_random_bytes() read from /dev/(u)random Use a HRNG 20
39. openssl_pseudo_random_bytes() read from /dev/(u)random Use a HRNG “A million random digits” 20
40. openssl_pseudo_random_bytes() read from /dev/(u)random Use a HRNG “A million random digits” https://github.com/ircmaxell/RandomLib 20
42. TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256 22
43. TLS ECDHE_ECDSA WITH AES_128_GCM SHA256 23
44. TLS ECDHE_ECDSA WITH AES_128_GCM SHA256 Cipher for exchanging key information 23
45. TLS ECDHE_ECDSA WITH AES_128_GCM SHA256 Cipher for exchanging key information Cipher for authenticating key information 23
46. TLS ECDHE_ECDSA WITH AES_128_GCM SHA256 Cipher for exchanging key information Cipher for authenticating key information Actual cipher (and length) used for communication 23
47. TLS ECDHE_ECDSA WITH AES_128_GCM SHA256 Cipher for exchanging key information Cipher for authenticating key information Hash algo for message authenticating Actual cipher (and length) used for communication 23
48. TLS_RSA_WITH_AES_256_CBC_SHA256 24
49. TLS_NULL_WITH_NULL_NULL 25
50. Client gives cipher options, Server ultimately decides on cipher! 26
51. THIS IS WHY YOU SHOULD ALWAYS CONFIGURE YOUR CIPHERS ON YOUR WEB SERVER! 27 Unknown fact!
52. 28 https://cipherli.st SSLCipherSuite AES256+EECDH:AES256+EDH SSLProtocol All -SSLv2 -SSLv3 SSLCompression off # Requires Apache >= 2.4 SSLHonorCipherOrder On SSLUseStapling on # Requires Apache >= 2.4 SSLStaplingCache "shmcb:logs/stapling-cache(150000)" # Requires >= Apache 2.4 Header always set Strict-Transport-Security "max-age=63072000; includeSubDomains" Header always set X-Frame-Options DENY ssl_ciphers 'AES256+EECDH:AES256+EDH'; ssl_protocols TLSv1 TLSv1.1 TLSv1.2; ssl_prefer_server_ciphers on; ssl_session_cache builtin:1000 shared:SSL:10m; add_header Strict-Transport-Security "max-age=63072000; includeSubDomains"; add_header X-Frame-Options DENY; ssl_stapling on; # Requires nginx >= 1.3.7 ssl_stapling_verify on; # Requires nginx => 1.3.7 resolver $DNS-IP-1 $DNS-IP-2 valid=300s; resolver_timeout 5s; Apache: nginx:
53. https://www.ssllabs.com/ssltest/ 29
56. 32 https://www.overheid.nl/
61. 37 ➡ SNI (Server Name Indication) ➡ Extension 0x0000 ➡ Pretty much every decent browser / server. ➡ IE6, Win XP, Blackberry, Android 2.x, java 1.6.x ➡ So no worries!
64. What an SSL certificate is NOT: 40 ➡ SSL certificate (but a X.509 certificate) ➡ Automatically secure ➡ Automatically trustworthy ➡ In any way better self-signed certificates ➡ Cheap
65. What an SSL certificate is: 41 ➡ The best way (but not perfect) to prove authenticity ➡ A way to bootstrap encrypted communication ➡ Misleading ➡ (Too) Expensive
67. 42 ➡ X.509 Certificate
68. 42 ➡ X.509 Certificate ➡ Owner info (who is this owner)
69. 42 ➡ X.509 Certificate ➡ Owner info (who is this owner) ➡ Domain info (for which domain(s) is this certificate valid)
70. 42 ➡ X.509 Certificate ➡ Owner info (who is this owner) ➡ Domain info (for which domain(s) is this certificate valid) ➡ Expiry info (from when to when is this certificate valid)
71. 43 yourdomain.com
72. 43 yourdomain.com Intermediate CA
73. 43 yourdomain.com Intermediate CA
74. 43 yourdomain.com Root CA Intermediate CA
75. 43 yourdomain.com Root CA Intermediate CA
76. 43 yourdomain.com Root CA Intermediate CA
77. 44 IMPLIED TRU$T
78. ➡ (Root) Certificate Authorities ➡ They are built into your browser / OS and you will automatically trust them. 45
79. 46 wget http://mxr.mozilla.org/mozilla-central/source/security/nss/lib/ckfw/builtins/certdata.txt\?raw\=1 -O - -q | grep Issuer | sort | uniq | wc -l
80. 46 wget http://mxr.mozilla.org/mozilla-central/source/security/nss/lib/ckfw/builtins/certdata.txt\?raw\=1 -O - -q | grep Issuer | sort | uniq | wc -l 181 And rising...
82. 47 ➡ X.509 certificates are used to authenticate the server.
83. 47 ➡ X.509 certificates are used to authenticate the server. ➡ Servers can ask clients to authenticate themselves as well.
84. 47 ➡ X.509 certificates are used to authenticate the server. ➡ Servers can ask clients to authenticate themselves as well. ➡ APIs
87. 50 Generating secrets:
88. 50 pre master secret server rand client rand Generating secrets: + +
89. 50 pre master secret server rand client rand master secret Generating secrets: + +
90. 50 pre master secret server rand client rand master secret master secret server rand client rand Generating secrets: + + + +
91. 50 pre master secret server rand client rand master secret master secret server rand client rand key buffer Generating secrets: + + + +
92. 50 pre master secret server rand client rand master secret client MAC client KEY client IV server MAC server KEY server IV master secret server rand client rand key buffer Generating secrets: + + + +
93. https://github.com/jaytaph/TLS-decoder 51 http://www.adayinthelifeof.nl/2013/12/30/decoding-tls-with-php/ Try it yourself, php style:
98. 56 Wireshark CAN decrypt your HTTPS traffic Unknown fact! SSLKEYLOGFILE https://isc.sans.edu/forums/diary/Psst+Your+Browser+Knows+All+Your+Secrets+/16415
99. 57 launchctl setenv SSLKEYLOGFILE /tmp/keylog.secret on a mac:
101. ➡ TLS has overhead in computation and transfers. But definitely worth it. ➡ Google likes it. ➡ Some ciphersuites are better, but slower. ➡ Speed / Security compromise ➡ (try: “openssl speed”) 59
102. Are we safe yet? 60
103. euh,.. no :/ 61
104. 62 PRE MASTER SECRET
105. What if somebody* got hold of the site private key? 63
110. (PERFECT) FORWARDING SECRECY 68
111. Compromising the pre-master secret does not compromise our communication. 69
112. PFS: Can’t compromise other keys with a compromised key. 70
113. Unfortunately.. 71
114. 72 PFS needs server AND browser support
115. 73 http://news.netcraft.com/archives/2013/06/25/ssl-intercepted-today-decrypted-tomorrow.html
116. 74 http://news.netcraft.com/archives/2013/06/25/ssl-intercepted-today-decrypted-tomorrow.html
117. Update your cipher suite list and place PFS ciphers at the top 75
118. But beware: heavy computations 76
119. 77 SSL Test https://www.ssllabs.com/ssltest/
120. -ETOOMUCHINFO 78
121. 79 https://www.ssllabs.com/projects/best-practices/index.html
122. http://farm1.static.flickr.com/73/163450213_18478d3aa6_d.jpg 80
123. 81 Find me on twitter: @jaytaph Find me for development and training: www.noxlogic.nl Find me on email: jthijssen@noxlogic.nl Find me for blogs: www.adayinthelifeof.nl