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Changes in Deployment of Cryptography

Changes in Deployment of Cryptography. Eric Murray Usenix Security Symposium 2001. Introduction. How to measure changes in crypto deployment? SSL/TLS webservers commonly used crypto software/hardware deployed by security-concious admins, not end-users as browsers are easy to check Why?.

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Changes in Deployment of Cryptography

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  1. Changes in Deployment of Cryptography Eric Murray Usenix Security Symposium 2001

  2. Introduction • How to measure changes in crypto deployment? • SSL/TLS webservers • commonly used crypto software/hardware • deployed by security-concious admins, not end-users as browsers are • easy to check • Why?

  3. Methodology • Generate list of https URLs • Search engine queries using words from /usr/dict/words (AltaVista ‘00, Google ‘01) • List of links to pages containing https URLs • Find https: URLs in pages • Sort for duplicates • Run sslstats on each https URL

  4. Methodology • sslstats • based on OpenSSL • grabs cert and parses for • Validity • key size/algorithm • Issuer and Subject name • SSLv2: connect and get list of ciphersuites

  5. Methodology • sslstats continued: • SSLv3: connect using each ciphersuite in turn • TLS: connect as SSLv3, add TLS ciphersuites • check for same cert as SSLv2 • Perl script reads sslstats output and generates stats

  6. Definitions • Servers categorized strong, meduim, weak • “weak” server defined as: • RSA key <= 512 bits • no SSLv3/TLS ciphersuites over >= 56 bits • expired certificate • self-signed certificate • only SSLv2

  7. Definitions • “medium”: • SSLv3/TLS • RSA key > 512 but <= 1000 bits • v3/TLS ciphersuites >= 56 bits but < 64 bits • “strong”: • SSLv3/TLS • RSA key > 1000 bits • v3/TLS ciphersuites >= 64 bits

  8. Results • 2000 survey: • 57% strong • 10% medium • 31% weak • 2001 survey: • 71% strong • 5% medium • 23% weak

  9. Results: Weak Server Types • Weak servers by type: 2000 2001 Microsoft-IIS 37% 35% Apache 17% 23% no name 15% 5% Netscape-Enterprise 13% 21% Stronghold 7% 4% WebSitePro 3% 1% “unknown” 2% 4%

  10. Results: Weak Server Details Percent of weak servers surveyed: 2000: 2001: Server key <= 512 bits: 81% 72% weak v3/TLS ciphersuites: 28% 26% expired cert: 10% 16% self-signed cert: 3% 8% only does SSLv2: 1% 6%

  11. Results: Server Details Percent of all servers surveyed: 2000: 2001: Server key <= 512 bits: 25% 17% weak SSLv3/TLS suites: 9% 6% expired cert: 3.1% 3.7% self-signed cert: .8% 2.0% only does SSLv2: .4% 1.4%

  12. RSA Server Key size Key bits 2000 2001 2048 .2% .2% 1024 70% 80% >= 1000 2% .7% >= 768 2% 1% >512 - 0% <= 512 25% 17%

  13. Protocol Support 2000 2001 Servers supporting: SSLv2 96% 93% SSLv3 99% 98% TLSv1 71% 76%

  14. SSLv2 Ciphersuite Support Ciphersuite: 2000 2001 RC4 Export 40 MD5 99% 98% RC2 Export 40 MD5 97% 96% RC4 128 MD5 86% 90% DES EDE3 MD5 85% 89% DES 64 MD5 85% 88% RC2 128 MD5 84% 88%

  15. SSLv3 Export Ciphersuites Ciphersuite: 2000 2001 RSA RC4 40 MD5 99% 79% RSA RC2 40 MD5 73% 87% RSA DES 40 SHA 56% 44% DHE RSA DES 40 SHA 24% 30%

  16. SSLv3 non-Export ciphersuites Ciphersuite: 2000 2001 RSA DES SHA 75% 76% RSA 3DES SHA 74% 61% RSA RC4 SHA 63% 64% DHE RSA DES SHA 24% 29% DHE RSA 3DES SHA 24% 30% RSA IDEA SHA 21% 26%

  17. TLSv1 Export Ciphersuites Ciphersuite: 2000 2001 RSA RC4 40 MD5 100% 100% RSA Exp1024 RC4 MD5 100% 100% RSA Exp1024 DES SHA 91% 85% RSA Exp1024 RC2 MD5 90% 84% RSA Exp1024 RC4 SHA 83% 83% RSA RC2 40 MD5 75% 76%

  18. TLSv1 non-export suites Ciphersuites: 2000 2001 RSA DES SHA 77% 78% RSA 3DES SHA 76% 78% RSA RC4 SHA 72% 75% DHE RSA DES SHA 25% 36% DHE DSS 3DES SHA 25% 36% RSA IDEA SHA 25% 32%

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