Looking at a dataset of 350 million ssl connections inspires some initial questions:

  • who made the certs
  • what crypto powers it
  • what sort of life time

Let’s Encrypt makes certs for almost 30% of web domains

The server you’re reading this on uses automated certs from Let’s Encrypt—they are more common on a domain than any other registrar! Over 47 million domains are protected with Let’s Encrypt certs, almost 30%.

Out of 352.3M domains, the dataset has 158.7M connections that proceeded far enough to provide a certificate with an issuer’s Distinguished Name. The top dozen1 are:

47.2MLet’s Encrypt
28.9MDigiCert
13.8MComodo
10.1MGoogle
7.2MGoDaddy
7.1MSectigo
7.0McPanel
6.1MGlobalSign
3.4MCloudFlare0
2.5MAmazon
2.1M(anonymous self-signed)
1.1MPlesk

Let’s Encrypt certs expire after 3 months, which pushes a regular update cycle, but there are still a number of ancient security practices around the web today.

Almost 3 million domains connected with RC4 or 3DES

Of the hundred and sixty million connections, over a hundred and fifty million connections used Elliptic-Curve Diffie Hellmann and AES. The next most popular cipher suite was RSA with RC4, and almost 1.8% of connections used RC4 or 3DES, with DES on half a dozen domains!2

120457325TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
16750820TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256
13808304TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA
2393679TLS_RSA_WITH_RC4_128_SHA
1768423TLS_RSA_WITH_AES_256_CBC_SHA
1653084TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA
1397638TLS_RSA_WITH_AES_128_CBC_SHA
373383TLS_ECDHE_RSA_WITH_RC4_128_SHA
157929TLS_RSA_WITH_3DES_EDE_CBC_SHA
17663TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA
4041TLS_ECDHE_ECDSA_WITH_RC4_128_SHA
2794TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA
458TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA
205TLS_RSA_WITH_RC4_128_MD5
115TLS_DH_RSA_WITH_AES_128_CBC_SHA
28unknown
6TLS_RSA_WITH_DES_CBC_SHA
1TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384

Note that the latest Chrome cannot load RC4 but it does load 3DES. (Thanks, badssl.com!)

Over 4 million domains are using outdated TLS

By default, go’s TLS package doesn’t use TLS 1.3, and it seems like the dataset was run with a zgrab that doesn’t use TLS 1.3 (perhaps this is worth updating for the next run). Most domains’ servers were using TLS 1.2, the next latest, but over 4 million were using TLS 1.0.3

154500876TLSv1.2
4263887TLSv1.0
19352TLSv1.1
1781SSLv3

Currently, TLS 1.0 is still allowed in Chrome.

Hundreds of thousands of domains’ certs expire after 2099

Current SSL cert lifetime best practices put lifetimes at 90 days.

But best practices do not forbid alternative practices!

Certs are in the wild with millenium-scale lifetimes, like these bristlecone pines.
(Rick Goldwaser from Flagstaff, AZ, USA [CC BY 2.0], via Wikimedia Commons)

Thousands of certs served expire after the year 3000

Over 3K certs served don’t expire this millenium. Over 8K certs expire after 2200. Over 200K certs expire after 2100. (Over 1.5M expire in the 2040s alone!)

Over a hundred thousand certs alone expire in 2117, and over a thousand expire in 3017. Perhaps something in 2017 inspired confidence in long-lived certs?

Millions of certs served have expired

Almost 1.6M domains had a cert that had recently expired (in July, the month of the scan). Almost 3.7M domains had a cert that expired in 2019 (the year of the scan). Over 9.6M domains had a cert that expired in the 2010s!

Hundreds of certs served are not yet valid

And what’s more, over a hundred thousand certs expire before their validity date!

Try this at home

Let me know what you think! Analyze this dataset and share your new findings!


  1. The aggregate issuer_dns that appeared more than 100K times are

    193590544 null
    47237383 C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
    13367305 C=US, O=DigiCert Inc, OU=www.digicert.com, CN=DigiCert SHA2 High Assurance Server CA
    13092572 C=GB, ST=Greater Manchester, L=Salford, O=COMODO CA Limited, CN=COMODO RSA Domain Validation Secure Server CA
    10081610 C=US, O=Google Trust Services, CN=Google Internet Authority G3
    7048258 C=US, ST=TX, L=Houston, O=cPanel, Inc., CN=cPanel, Inc. Certification Authority
    6772537 C=GB, ST=Greater Manchester, L=Salford, O=Sectigo Limited, CN=Sectigo RSA Domain Validation Secure Server CA
    4946970 C=US, O=DigiCert Inc, OU=www.digicert.com, CN=RapidSSL RSA CA 2018
    3926261 C=GB, ST=Greater Manchester, L=Salford, O=COMODO CA Limited, CN=COMODO ECC Domain Validation Secure Server CA 2
    3727005 C=US, ST=Arizona, L=Scottsdale, O=GoDaddy.com, Inc., OU=http://certs.godaddy.com/repository/, CN=Go Daddy Secure Certificate Authority - G2
    3483129 C=US, ST=Arizona, L=Scottsdale, O=Starfield Technologies, Inc., OU=http://certs.starfieldtech.com/repository/, CN=Starfield Secure Certificate Authority - G2
    3404488 C=US, ST=CA, L=San Francisco, O=CloudFlare, Inc., CN=CloudFlare Inc ECC CA-2
    2523036 C=US, O=Amazon, OU=Server CA 1B, CN=Amazon
    2498667 C=US, O=DigiCert Inc, OU=www.digicert.com, CN=Thawte TLS RSA CA G1
    2431104 C=BE, O=GlobalSign nv-sa, CN=GlobalSign Domain Validation CA - SHA256 - G2
    2422131 C=BE, O=GlobalSign nv-sa, CN=AlphaSSL CA - SHA256 - G2
    2310140 C=US, O=DigiCert Inc, CN=DigiCert SHA2 Secure Server CA
    1791127 C=US, O=DigiCert Inc, OU=www.digicert.com, CN=Encryption Everywhere DV TLS CA - G1
    1298054 C=GB, ST=Greater Manchester, L=Salford, O=COMODO CA Limited, CN=COMODO RSA Organization Validation Secure Server CA
    1019337 C=US, O=DigiCert Inc, OU=www.digicert.com, CN=GeoTrust RSA CA 2018
     853367 C=US, O=DigiCert Inc, CN=DigiCert ECC Secure Server CA
     842994 C=US, ST=Someprovince, L=Sometown, O=none, OU=none, CN=localhost, emailAddress=webmaster@localhost
     828175 C=CH, L=Schaffhausen, O=Plesk, CN=Plesk, emailAddress=info@plesk.com
     800601 C=US, O=DigiCert Inc, OU=www.digicert.com, CN=Thawte RSA CA 2018
     736336 C=BE, O=GlobalSign nv-sa, CN=GlobalSign Organization Validation CA - SHA256 - G2
     679798 C=FR, ST=Paris, L=Paris, O=Gandi, CN=Gandi Standard SSL CA 2
     648187 OU=Default Web server, CN=www.example.com, emailAddress=postmaster@example.com
     572342 C=--, ST=SomeState, L=SomeCity, O=SomeOrganization, OU=SomeOrganizationalUnit, CN=server.ab-archive.net, emailAddress=root@server.ab-archive.net
     546456 C=DE, ST=Bayern, L=Muenchen, O=ispgateway, CN=webserver.ispgateway.de, emailAddress=hostmaster@ispgateway.de
     501592 C=US, ST=Virginia, L=Herndon, O=Parallels, OU=Parallels Panel, CN=Parallels Panel, emailAddress=info@parallels.com
     501093 C=US, ST=California, O=DreamHost, CN=sni.dreamhost.com
     480468 C=CN, O=TrustAsia Technologies, Inc., OU=Domain Validated SSL, CN=TrustAsia TLS RSA CA
     468190 C=BE, O=GlobalSign nv-sa, CN=GlobalSign CloudSSL CA - SHA256 - G3
     464242 C=--, ST=SomeState, L=SomeCity, O=SomeOrganization, OU=SomeOrganizationalUnit, CN=localhost.localdomain, emailAddress=root@localhost.localdomain
     455067 C=PL, O=home.pl S.A., CN=Certyfikat SSL
     445550 C=US, O=DigiCert Inc, OU=www.digicert.com, CN=Encryption Everywhere DV TLS CA - G2
     417062 C=PL, O=Unizeto Technologies S.A., OU=Certum Certification Authority, CN=Certum Domain Validation CA SHA2
     416966 C=JP, ST=Tokyo, L=Chiyoda-ku, O=Gehirn Inc., CN=Gehirn Managed Certification Authority - RSA DV
     384480 C=IT, ST=Bergamo, L=Ponte San Pietro, O=Actalis S.p.A./03358520967, CN=Actalis Organization Validated Server CA G2
     368708 C=JP, ST=OSAKA, L=OSAKA, O=SecureCore, CN=SecureCore RSA DV CA
     353716 C=US, O=DigiCert Inc, OU=www.digicert.com, CN=RapidSSL TLS RSA CA G1
     343034 C=US, O=DigiCert Inc, CN=DigiCert Global CA G2
     278170 C=PL, O=nazwa.pl sp. z o.o., OU=http://nazwa.pl, CN=nazwaSSL
     267784 C=US, ST=Illinois, L=Chicago, O=Trustwave Holdings, Inc., CN=Trustwave Organization Validation SHA256 CA, Level 1, emailAddress=ca@trustwave.com
     251987 C=IT, ST=Bergamo, L=Ponte San Pietro, O=Actalis S.p.A./03358520967, CN=Actalis Domain Validation Server CA G2
     244273 C=JP, O=Cybertrust Japan Co., Ltd., CN=Cybertrust Japan Public CA G3
     236608 C=US, ST=Washington, L=Seattle, O=Odin, OU=Plesk, CN=Plesk, emailAddress=info@plesk.com
     228615 C=GB, ST=Greater Manchester, L=Salford, O=Sectigo Limited, CN=Sectigo RSA Organization Validation Secure Server CA
     202529 C=US, O=DigiCert Inc, OU=www.digicert.com, CN=GeoTrust TLS RSA CA G1
     184627 C=US, ST=MI, L=Ann Arbor, O=Internet2, OU=InCommon, CN=InCommon RSA Server CA
     184276 C=US, O=Entrust, Inc., OU=See www.entrust.net/legal-terms, OU=(c) 2012 Entrust, Inc. - for authorized use only, CN=Entrust Certification Authority - L1K
     177315 C=NL, ST=Noord-Holland, L=Amsterdam, O=TERENA, CN=TERENA SSL CA 3
     171469 C=LV, L=Riga, O=GoGetSSL, CN=GoGetSSL RSA DV CA
     168933 C=US, O=GeoTrust Inc., CN=RapidSSL SHA256 CA
     150830 C=RU, ST=Moscow, L=Moscow, O=Odin, OU=Odin Automation, CN=odin.com, emailAddress=webmaster@odin.com
     122399 C=JP, O=Japan Registry Services Co., Ltd., CN=JPRS Domain Validation Authority - G2
     118029 C=GB, ST=Greater Manchester, L=Salford, O=Sectigo Limited, CN=Sectigo ECC Domain Validation Secure Server CA
     109435 C=GB, ST=Berkshire, L=Newbury, O=My Company Ltd
     108309 C=US, ST=Washington, L=Redmond, O=Microsoft Corporation, OU=Microsoft IT, CN=Microsoft IT TLS CA 2
     108016 C=US, O=GeoTrust Inc., CN=RapidSSL SHA256 CA - G3
     107719 C=--, ST=SomeState, L=SomeCity, O=SomeOrganization, OU=SomeOrganizationalUnit, CN=ns546485.ip-158-69-252.net, emailAddress=root@ns546485.ip-158-69-252.net
     106164 C=US, ST=DE, L=Wilmington, O=Corporation Service Company, CN=Trusted Secure Certificate Authority DV
     104634 CN=localhost
    

    In the zgrab schema they are .data.tls.server_certificates.certificate.parsed.issuer_dn , and you can reproduce the results with zcat 2019-08-01-ssl-*.gz | parallel --pipe jq -r .data.tls.server_certificates.certificate.parsed.issuer_dn | sort | uniq -c

  2. zcat 2019-08-01-ssl-*.gz | parallel --pipe jq -r .data.tls.server_hello.cipher_suite.name | sort | uniq -c 

  3. zcat 2019-08-01-ssl-*.gz | parallel --pipe jq -r .data.tls.server_hello.version.name | sort | uniq -c