Auditing OpenSSL and Beyond

Thoughts on the core internet security software trust chain
Circle City Con 2015

Transcript

1. Rethinking  the  Trust  Chain:   Auditing  OpenSSL  and  Beyond Kenneth White June 12, 2015
2. Topics •  Bootstrapping Trust •  Digging deeper •  OpenSSL audit update •  Core infrastructure work •  Emerging
3. Ping  me Twitter @kennwhite Talks speakerdeck.com/kwhite OCAP https://opencryptoaudit.org/people
4. Open  Crypto  Audit  Project •  OCAP originally formed to manage community- funded TrueCrypt audit •  Independent technical research public interest organization •  Technical Advisory Board: academic, industry, and legal experts in security •  Mission: Research, analysis & education around technical security in open source software •  Focus: software security, cryptography engineering, public awareness •  Current project: OpenSSL audit
5. The  Software  Security   Trust  Chain 1 year post-Heartbleed • Most serious CVEs are rarely about the crypto • But the (most widely deployed) crypto trust chain is fragile • Key pieces of the core Internet network stack are virtually unexamined, and little understood
6. The  Software  Security   Trust  Chain 1 year post-Heartbleed • Most serious CVEs are (rarely) about the crypto • But the (most widely deployed) crypto trust chain is fragile • Key pieces of the core Internet network stack are virtually unexamined, and little understood
7. The  Software  Security   Trust  Chain Questions How well do you know the network stack you’ve deployed? How about your technical staff? Do you/they understand your core dependencies?
8. The  Software  Security   Trust  Chain Questions How well do you know the network stack you’ve deployed? How about your technical staff? Do you/they understand your core dependencies?
9. The  Software  Security   Trust  Chain Are you sure?
10. The  Software  Security   Trust  Chain Are you sure? First question: Explain the dependencies of init/systemd.
13. Mature network hardware
14. A $100K commercial load balancer compromised by a browser ID string
15. The  Software  Security   Trust  Chain Questions How well do you know the network stack you’ve deployed? How about your technical staff? Do you/they understand your core dependencies?
16. The  Software  Security   Trust  Chain Are you sure?
17. The  Software  Security   Trust  Chain Are you sure? First question: Explain the dependencies of init/systemd.
18. Let’s really look at the whole security trust chain…
19. Internet  Core  Trust  Chain For example: o  XML parsers (libxml2, Expat, SimpleXML…) o  Image generators (libpng…) o  Internationalization libraries (libIDN) o  Compression (libzma) o  ASN.1 & x509 (everywhere) o  Middleware core: BouncyCastle, Spring, Struts… o  Deeper: libBFD, libCurl, IPSec netkey, pluto, l2tp
20. Internet  Core  Trust  Chain Time to look really closely, at, say: o  XML parsers (libxml2, Expat, SimpleXML…) o  Image generators (libpng…) o  Internationalization libraries (libIDN) o  Compression (libzma) o  ASN.1 & x509 (everywhere) o  Middleware core: BouncyCastle, Spring, Struts… o  Deeper: libCurl, libBFD, IPSec netkey, pluto, l2tp
21. libcurl
23. libbfd
25. BFD  is  a  BFD
26. Are you kidding me?!
27. “Wait, there’s more!” Let’s look at the shell utility ‘less’
30. BFD  is  a  BFD.    
31. BFD  is  a  BFD.   But  most  Linux  admins  have   never  even  heard  of  it
32. “All  versions  of  Windows”
33. Let’s go higher up
34. Basic server certificate deployment is a solved problem, yes?
35. Basic server certificate deployment is a solved problem, yes?
36. Don’t underestimate the impact of applied research
37. Don’t underestimate the impact of applied research
38. Network transport has integrity, yes?
39. Network transport has integrity, yes?
40. Network transport has integrity, yes? https://gist.github.com/kennwhite/1f3bc4d889b02b35d8aa
41. Ad networks are trusted for arbitrary client code, yes?
43. The  Komodia  case
44. The  Komodia  case
48. The  nuclear  option…
50. But  trust  is  complicated…
51. But  trust  is  complicated…
52. But  trust  is  complicated…
53. And  this  isn’t  helping
54. The  Security  Trust  Chain   is  Broken   But  we’re  working  on  it
55. PSA:  Encryption  is  rarely   the  problem
58. The  Security  Trust  Chain   is  Broken   But  we’re  working  on  it
59. 2015  Mainstream  Distro   Apache/Nginx  SSL  in  1  Easy  Slide
60. 2015  Mainstream  Distro   Apache/Nginx  SSL  in  1  Easy  Slide PROTOCOL SSL v1 SSL v2 SSL v3 TLS 1.0 TLS 1.1 TLS 1.2 TLS 1.3 CIPHER NULL DES 3DES RC4 Twofish Blowfish AES KEYEX RSA DH DHE ECDH HMAC MD5 SHA-1 SHA-256 SHA-384 SHA-512 MODE ECB CBC GCM AUTH ECDSA RSA
61. 2015  Mainstream  Distro   Apache/Nginx  SSL  in  1  Easy  Slide PROTOCOL SSL v1 SSL v2 SSL v3 TLS 1.0 TLS 1.1 TLS 1.2 TLS 1.3 CIPHER NULL DES 3DES RC4 Twofish Blowfish AES KEYEX RSA DH DHE ECDH HMAC MD5 SHA-1 SHA-256 SHA-384 SHA-512 MODE ECB CBC GCM AUTH ECDSA RSA
62. 2015  Mainstream  Distro   Apache/Nginx  SSL  in  1  Easy  Slide PROTOCOL SSL v1 SSL v2 SSL v3 TLS 1.0 TLS 1.1 TLS 1.2 TLS 1.3 CIPHER NULL DES 3DES RC4 Twofish Blowfish AES KEYEX RSA DH DHE ECDH HMAC MD5 SHA-1 SHA-256 SHA-384 SHA-512 MODE ECB CBC GCM AUTH ECDSA RSA Also: HSTS (strict secure transport), HPKP (pinning), CT (cert transparency), SNI (virtual hosts)
63. Just kidding. 2015  Mainstream  Distro   Apache/Nginx  SSL  in  1  Easy  Slide
64. Just kidding. Understand your install base, interop and threat model. Then read tactical guidance by Mozilla, SSLLabs, Robert Love, Adam Langley, Thomas Ptacek 2015  Mainstream  Distro   Apache/Nginx  SSL  in  1  Easy  Slide
65. Just kidding. Understand your install base, interop and threat model. Then read tactical guidance by Mozilla, SSLLabs, Robert Love, Adam Langley, Thomas Ptacek… 2015  Mainstream  Distro   Apache/Nginx  SSL  in  1  Easy  Slide
66. For example Adam Langley: Matching primitive strengths www.imperialviolet.org/2014/05/25/strengthmatching.html Ivan Ristic Introducing TLS Maturity Model community.qualys.com/blogs/securitylabs/2015/06/08/introducing-tls-maturity- model Bulletproof SSL and TLS www.feistyduck.com/books/bulletproof-ssl-and-tls Thomas Ptacek: Cryptographic Right Answers gist.github.com/tqbf/be58d2d39690c3b366ad Mozilla: Security/Sever Side TLS wiki.mozilla.org/Security/Server_Side_TLS
67. The  OpenSSL  Audit
68. The  OpenSSL  Audit •  Commissioned by Linux Foundation’s Core Infrastructure Initiative (CII) •  Ambitious Scope o Independent review o Coordinating closely with OpenSSL core team o Delayed for v. 1.1 maturity (significant refactor) o Diverse, complex codebase o Linux, BSDs, Windows, OSX, SRV5 (AIX, HP-UX, Solaris) o Intel x86 (incl. AES-NI), ARMv7, MIPS, PowerPC, Alpha… o FIPS module
69. OpenSSL  Audit •  Goals •  Thorough public security analysis of the core code in the next major release of OpenSSL •  Demonstrate viability of a reusable open source test harness framework •  Foster web-scale peer-reviewed public tools & data sets for protocol & negotiation analysis
70. OpenSSL  Audit Rough metrics: 412-494K total SLOC OpenSSL v. 1.1 master (2015-03-14)
71. OpenSSL  Audit •  Phase 1 •  BigNum: multiprecision ints, constant time, blinding •  BIO (focus on composition & file functions) •  ASN.1 & x509 (cert & key parsing, DER/PEM decoding, structs, subordinate chains) •  93M cert corpus, “Frankencert” fuzzing •  Phase 2 •  TLS state machine •  EVP (PKI constructions, H/MACs, envelopes) •  Protocol flows, core engine implementation •  Memory management •  Crypto core (RSA, SHA-2, DH/ECDH, CBC, GGM…)
72. OpenSSL  Audit Caveats •  Schedule, funding, or quality: Pick 2 •  High Priority •  Major architectures •  Modern (TLS 1.3) protocols & primitives •  DH, ECC, signatures, ASN.1 & x509 •  Non-crypto constructions (data structures, memory management, core API/ABI hooks) •  Lower Priority •  AES implementation (finite field tables, matrix transformations, etc. TBD, possibly in phase 3 formal academic analysis) •  RC4 •  S/MIME •  OpenSSL s_server (smtp-aware web server!)
73. Emerging
74. Better primitives and core crypto •  HTTP/2 & TLS 1.3 •  NaCl/LibSodium, ChaCha20/Poly1305 (OpenSSL soon) •  Marlinspike et al’s work on OTR, axolotl ratchet •  Trevor Perrin’s work on public key pinning & TLS core Containers smaller surface (Docker, Rocket, LXC) Let’s Encrypt (Mozilla, Akamai, Cisco, EFF) USG: All fed websites & services HTTPS-only Open threat feeds (AlienVault Open Threat Exchange v2) Verizon Data Breach Investigation Report model Emerging
75. Dan Bernstein: NaCL networking and cryptography library http://nacl.cr.yp.to Frank Denis: Sodium crypto library https://www.gitbook.com/book/jedisct1/libsodium/details Moxie Marlinspike and Trevor Perrin: Advanced cryptographic ratcheting https://whispersystems.org/blog/advanced-ratcheting Andrew Gerrand: The State of Go http://talks.golang.org/2015/state-of-go-may.slide Daniel Stenberg: TLS in HTTP/2 http://daniel.haxx.se/blog/2015/03/06/tls-in-http2 GoLang team: Go crypto library https://godoc.org/golang.org/x/crypto
76. Docker: The tutorial www.docker.com/tryit CoreOS is building a container runtime, rkt coreos.com/blog/rocket Let's Encrypt: A public open certificate authority letsencrypt.org US CIO: HTTPS-Everywhere for Government cio.gov/https-everywhere-for-government Open Threat Exchange: OTX v. 2.0 www.alienvault.com/blogs/security-essentials/otx-20-beta-finally-a-way- beyond-the-rhetoric-of-threat-intelligence Verizon DBIR 2015 www.verizonenterprise.com/resources/reports/rp_data-breach-investigation- report-2015_en_xg.pdf
77. Parting  Thoughts o  Encryption is rarely the problem o  Understand your threat model o  VZ DBIR: 99.9% of successful exploits last year relied on a CVE more than a year old o  Intelligence & defense collaboration & sharing is critical o  Stronger security chain will require better cooperation, more open exchanges, and trust
78. Parting  Thoughts We are very much in the golden age of web security.
79. Parting  Thoughts We are very much in the golden age of web security. We are beginning a serious re-examination of the core stack and fundamental trust chains.
80. The  Security  Trust  Chain   is  Broken  
81. The  Security  Trust  Chain   is  Broken   But  we’re  working  on  it
82. Special  thanks Paul Wouters (@letoams) Marsh Ray (@marshray) Chris Hoff (@Beaker) Wendy Nather (@451wendy) Thomas Ptacek (@tqbf) Filippo Valsorda(@FiloSottile) Scot Terban (@krypt3ia) Jeff Jarmoc (@jjarmoc)
83. Be  careful  out  there,  folks
84. Ping  me OCAP admin @ opencryptoaudit . org OCAP https://opencryptoaudit.org/people Twitter @kennwhite Talks speakerdeck.com/kwhite