Skip to main content

Raymii.org Raymii.org Logo

Quis custodiet ipsos custodes?
Home | About | All pages | Cluster Status | RSS Feed

OpenSSL: Get all certificates from a website in plain text

Published: 04-02-2014 | Author: Remy van Elst | Text only version of this article


❗ This post is over ten years old. It may no longer be up to date. Opinions may have changed.


This snippet shows you how to get all certificates of a website in plain text. With a few OpenSSL commands one can get the website certificate plus intermediate certificates, however, if you feed that output to OpenSSL it only works on the first certificate. Using a bit of sed and bash magic we can feed all certificates one by one to OpenSSL.

Recently I removed all Google Ads from this site due to their invasive tracking, as well as Google Analytics. Please, if you found this content useful, consider a small donation using any of the options below:

I'm developing an open source monitoring app called Leaf Node Monitoring, for windows, linux & android. Go check it out!

Consider sponsoring me on Github. It means the world to me if you show your appreciation and you'll help pay the server costs.

You can also sponsor me by getting a Digital Ocean VPS. With this referral link you'll get $200 credit for 60 days. Spend $25 after your credit expires and I'll get $25!

Website certificate

You can request a website's certificate using openssl s_client. To view the public key from google.com we can use the following command:

openssl s_client -connect google.com:443 </dev/null

It will output a bunch of text, including the certificate, protocol and connection information and a part of the chain. If we just want the certificate we can use the following command:

openssl s_client -connect google.com:443 2>&1 < /dev/null | sed -n '/-----BEGIN/,/-----END/p'

This will output only the public key.

Plain text

If we feed that output into openssl again, we can output the certificate information in plain text:

openssl s_client -connect google.com:443 2>&1 < /dev/null | sed -n '/-----BEGIN/,/-----END/p' | openssl x509 -noout -text

This is all the information about a certificate:

Certificate:
    Data:
        Version: 3 (0x2)
        Serial Number:
            66:79:66:fc:e2:c7:d0:2d
    Signature Algorithm: sha1WithRSAEncryption
        Issuer: C=US, O=Google Inc, CN=Google Internet Authority G2
        Validity
            Not Before: Jan 15 14:34:20 2014 GMT
            Not After : May 15 00:00:00 2014 GMT
        Subject: C=US, ST=California, L=Mountain View, O=Google Inc, CN=*.google.com
        Subject Public Key Info:
            Public Key Algorithm: rsaEncryption
                Public-Key: (2048 bit)
                Modulus:
                    00:a3:cb:4e:db:d1:59:dc:13:b2:89:1d:d0:31:2c:
                    fb:f2:b2:55:a8:76:3c:d3:2b:00:f8:87:e6:b0:80:
                    af:8f:46:ed:d8:35:72:1e:d0:55:26:a4:09:7e:71:
                    b4:6b:28:df:c4:54:b3:17:5f:31:77:d1:a2:eb:2a:
                    f4:e5:7c:5e:7c:2a:3d:39:b3:56:64:bf:65:45:86:
                    ef:e1:b4:94:7b:df:6e:b9:e9:c7:ef:b0:12:b8:31:
                    54:58:a9:39:bd:33:8f:df:53:76:da:49:ae:bf:5e:
                    f3:e7:f3:2f:6a:e5:9e:d9:fd:58:99:45:f7:a0:6f:
                    23:6e:88:8f:1d:3e:c3:50:28:a1:d6:ba:a6:56:50:
                    f4:c0:a9:73:37:96:75:42:5b:2f:65:18:54:17:fa:
                    51:f7:74:f2:59:18:dc:e4:33:fb:88:d5:60:e4:7e:
                    f7:65:57:02:fd:8d:f6:e3:74:53:c5:27:30:ec:85:
                    b0:db:43:f0:1f:af:e5:c1:f5:c7:06:8b:11:a8:20:
                    50:df:98:72:b7:4b:0f:73:e7:d9:7a:b8:3d:51:e7:
                    bc:d2:0f:12:27:d0:e2:f6:2e:0a:a9:c1:78:df:d6:
                    d1:5f:59:9f:a2:44:ef:7c:24:ca:b9:f8:7e:fe:c2:
                    84:66:f7:f8:9d:41:19:42:61:90:52:5c:68:33:b8:
                    b6:61
                Exponent: 65537 (0x10001)
        X509v3 extensions:
            X509v3 Extended Key Usage:
                TLS Web Server Authentication, TLS Web Client Authentication
            X509v3 Subject Alternative Name:
                DNS:*.google.com, DNS:*.android.com, DNS:*.appengine.google.com, DNS:*.cloud.google.com, DNS:*.google-analytics.com, DNS:*.google.ca, DNS:*.google.cl, DNS:*.google.co.in, DNS:*.google.co.jp, DNS:*.google.co.uk, DNS:*.google.com.ar, DNS:*.google.com.au, DNS:*.google.com.br, DNS:*.google.com.co, DNS:*.google.com.mx, DNS:*.google.com.tr, DNS:*.google.com.vn, DNS:*.google.de, DNS:*.google.es, DNS:*.google.fr, DNS:*.google.hu, DNS:*.google.it, DNS:*.google.nl, DNS:*.google.pl, DNS:*.google.pt, DNS:*.googleapis.cn, DNS:*.googlecommerce.com, DNS:*.googlevideo.com, DNS:*.gstatic.com, DNS:*.urchin.com, DNS:*.url.google.com, DNS:*.youtube-nocookie.com, DNS:*.youtube.com, DNS:*.youtubeeducation.com, DNS:*.ytimg.com, DNS:android.com, DNS:g.co, DNS:goo.gl, DNS:google-analytics.com, DNS:google.com, DNS:googlecommerce.com, DNS:urchin.com, DNS:youtu.be, DNS:youtube.com, DNS:youtubeeducation.com
            Authority Information Access:
                CA Issuers - URI:http://pki.google.com/GIAG2.crt
                OCSP - URI:http://clients1.google.com/ocsp

            X509v3 Subject Key Identifier:
                61:54:7B:A4:44:E8:68:E2:D3:0D:CC:77:D4:29:35:3B:58:23:60:B3
            X509v3 Basic Constraints: critical
                CA:FALSE
            X509v3 Authority Key Identifier:
                keyid:4A:DD:06:16:1B:BC:F6:68:B5:76:F5:81:B6:BB:62:1A:BA:5A:81:2F

            X509v3 Certificate Policies:
                Policy: 1.3.6.1.4.1.11129.2.5.1

            X509v3 CRL Distribution Points:

                Full Name:
                  URI:http://pki.google.com/GIAG2.crl

    Signature Algorithm: sha1WithRSAEncryption
         6f:7b:07:5c:59:ce:7d:52:b3:bc:26:c7:7c:e8:6e:32:aa:fc:
         3e:67:0a:51:1c:4b:6e:bb:7d:69:eb:fc:7a:02:76:59:bf:86:
         97:50:ed:bd:ec:88:7c:d3:a0:a3:a6:27:fe:a0:21:55:76:da:
         1b:7c:22:82:1e:31:73:d3:25:33:2d:72:de:63:36:18:50:9e:
         49:bf:e3:78:c7:b4:33:38:b7:f8:10:93:a0:fa:5d:a7:4d:78:
         48:74:7f:dd:c6:aa:8f:eb:26:de:e3:6b:4f:4b:c7:3a:0c:b7:
         4c:c3:a9:bf:2b:46:b8:50:37:0b:05:e5:92:e4:9c:f3:36:bb:
         f1:75:ad:20:31:99:1e:3d:83:6e:e1:dd:13:67:1a:2a:f7:c6:
         e1:1d:4d:c4:4f:f8:e0:88:c5:3e:17:8b:15:5e:71:3d:69:99:
         56:ba:fb:7f:07:d6:33:0a:d0:27:aa:9d:ce:77:a9:af:a1:93:
         10:8c:27:48:1a:1f:62:48:04:8f:64:51:6d:52:e9:60:6d:a9:
         98:7b:43:d6:cc:66:69:65:40:d6:57:ff:06:f5:73:59:8f:1b:
         87:9b:36:5b:41:06:4a:5e:25:69:bb:f0:70:49:72:0b:d8:67:
         7b:ed:d4:b3:c8:79:c8:58:5e:f3:f1:f5:98:fa:80:03:d3:7d:
         8a:d0:c8:76

Multiple certificates

Using the -showcerts option of s_client we can show all certificates the website sends, including the issuing and intermediate certificates:

openssl s_client -connect google.com:443 -showcerts 2>&1 < /dev/null

If we want to receive those certificates without all the other output we can use the same sed trick as before:

openssl s_client -connect google.com:443 -showcerts 2>&1 < /dev/null | sed -n '/-----BEGIN/,/-----END/p'

However, if we feed that into openssl again to receive the plain text output we only get output for the first certificate:

openssl s_client -connect google.com:443 -showcerts 2>&1 < /dev/null | sed -n '/-----BEGIN/,/-----END/p' | openssl x509 -noout -text

According to the OpenSSL documentation the x509 option only supports one certificate at a time. Using the following one liner we:

  • Set the Internal Field Separator to a colon (:).
  • Get all the certificates for google.com in a variable named certificates.
  • We use a group of sed commands to first print the certificates, then we substitute the beginning of the -----BEGIN line with a colon (:) and then the original ----BEGIN line resulting in :-----BEGIN.
  • We do a for loop on all certificates in the output, split by a colon (:).
  • We feed those one by one to OpenSSL
  • We change the Internal Field Seperator back to what it was.

This is the command:

OLDIFS=$IFS; IFS=':' certificates=$(openssl s_client -connect google.com:443
-showcerts -tlsextdebug 2>&1 </dev/null | sed -n '/-----BEGIN/,/-----END/
{/-----BEGIN/ s/^/:/; p}'); for certificate in ${certificates#:}; do echo
$certificate | openssl x509 -noout -text; done; IFS=$OLDIFS

Do note that you need the GNU version of sed. The OS X or BSD version will not work.

The output are all certificates in text format:

Certificate:
    Data:
        Version: 3 (0x2)
        Serial Number:
            66:79:66:fc:e2:c7:d0:2d
    Signature Algorithm: sha1WithRSAEncryption
        Issuer: C=US, O=Google Inc, CN=Google Internet Authority G2
        Validity
            Not Before: Jan 15 14:34:20 2014 GMT
            Not After : May 15 00:00:00 2014 GMT
        Subject: C=US, ST=California, L=Mountain View, O=Google Inc, CN=*.google.com
        Subject Public Key Info:
            Public Key Algorithm: rsaEncryption
                Public-Key: (2048 bit)
                Modulus:
                    00:a3:cb:4e:db:d1:59:dc:13:b2:89:1d:d0:31:2c:
                    fb:f2:b2:55:a8:76:3c:d3:2b:00:f8:87:e6:b0:80:
                    af:8f:46:ed:d8:35:72:1e:d0:55:26:a4:09:7e:71:
                    b4:6b:28:df:c4:54:b3:17:5f:31:77:d1:a2:eb:2a:
                    f4:e5:7c:5e:7c:2a:3d:39:b3:56:64:bf:65:45:86:
                    ef:e1:b4:94:7b:df:6e:b9:e9:c7:ef:b0:12:b8:31:
                    54:58:a9:39:bd:33:8f:df:53:76:da:49:ae:bf:5e:
                    f3:e7:f3:2f:6a:e5:9e:d9:fd:58:99:45:f7:a0:6f:
                    23:6e:88:8f:1d:3e:c3:50:28:a1:d6:ba:a6:56:50:
                    f4:c0:a9:73:37:96:75:42:5b:2f:65:18:54:17:fa:
                    51:f7:74:f2:59:18:dc:e4:33:fb:88:d5:60:e4:7e:
                    f7:65:57:02:fd:8d:f6:e3:74:53:c5:27:30:ec:85:
                    b0:db:43:f0:1f:af:e5:c1:f5:c7:06:8b:11:a8:20:
                    50:df:98:72:b7:4b:0f:73:e7:d9:7a:b8:3d:51:e7:
                    bc:d2:0f:12:27:d0:e2:f6:2e:0a:a9:c1:78:df:d6:
                    d1:5f:59:9f:a2:44:ef:7c:24:ca:b9:f8:7e:fe:c2:
                    84:66:f7:f8:9d:41:19:42:61:90:52:5c:68:33:b8:
                    b6:61
                Exponent: 65537 (0x10001)
        X509v3 extensions:
            X509v3 Extended Key Usage:
                TLS Web Server Authentication, TLS Web Client Authentication
            X509v3 Subject Alternative Name:
                DNS:*.google.com, DNS:*.android.com, DNS:*.appengine.google.com, DNS:*.cloud.google.com, DNS:*.google-analytics.com, DNS:*.google.ca, DNS:*.google.cl, DNS:*.google.co.in, DNS:*.google.co.jp, DNS:*.google.co.uk, DNS:*.google.com.ar, DNS:*.google.com.au, DNS:*.google.com.br, DNS:*.google.com.co, DNS:*.google.com.mx, DNS:*.google.com.tr, DNS:*.google.com.vn, DNS:*.google.de, DNS:*.google.es, DNS:*.google.fr, DNS:*.google.hu, DNS:*.google.it, DNS:*.google.nl, DNS:*.google.pl, DNS:*.google.pt, DNS:*.googleapis.cn, DNS:*.googlecommerce.com, DNS:*.googlevideo.com, DNS:*.gstatic.com, DNS:*.urchin.com, DNS:*.url.google.com, DNS:*.youtube-nocookie.com, DNS:*.youtube.com, DNS:*.youtubeeducation.com, DNS:*.ytimg.com, DNS:android.com, DNS:g.co, DNS:goo.gl, DNS:google-analytics.com, DNS:google.com, DNS:googlecommerce.com, DNS:urchin.com, DNS:youtu.be, DNS:youtube.com, DNS:youtubeeducation.com
            Authority Information Access:
                CA Issuers - URI:http://pki.google.com/GIAG2.crt
                OCSP - URI:http://clients1.google.com/ocsp

            X509v3 Subject Key Identifier:
                61:54:7B:A4:44:E8:68:E2:D3:0D:CC:77:D4:29:35:3B:58:23:60:B3
            X509v3 Basic Constraints: critical
                CA:FALSE
            X509v3 Authority Key Identifier:
                keyid:4A:DD:06:16:1B:BC:F6:68:B5:76:F5:81:B6:BB:62:1A:BA:5A:81:2F

            X509v3 Certificate Policies:
                Policy: 1.3.6.1.4.1.11129.2.5.1

            X509v3 CRL Distribution Points:

                Full Name:
                  URI:http://pki.google.com/GIAG2.crl

    Signature Algorithm: sha1WithRSAEncryption
         6f:7b:07:5c:59:ce:7d:52:b3:bc:26:c7:7c:e8:6e:32:aa:fc:
         3e:67:0a:51:1c:4b:6e:bb:7d:69:eb:fc:7a:02:76:59:bf:86:
         97:50:ed:bd:ec:88:7c:d3:a0:a3:a6:27:fe:a0:21:55:76:da:
         1b:7c:22:82:1e:31:73:d3:25:33:2d:72:de:63:36:18:50:9e:
         49:bf:e3:78:c7:b4:33:38:b7:f8:10:93:a0:fa:5d:a7:4d:78:
         48:74:7f:dd:c6:aa:8f:eb:26:de:e3:6b:4f:4b:c7:3a:0c:b7:
         4c:c3:a9:bf:2b:46:b8:50:37:0b:05:e5:92:e4:9c:f3:36:bb:
         f1:75:ad:20:31:99:1e:3d:83:6e:e1:dd:13:67:1a:2a:f7:c6:
         e1:1d:4d:c4:4f:f8:e0:88:c5:3e:17:8b:15:5e:71:3d:69:99:
         56:ba:fb:7f:07:d6:33:0a:d0:27:aa:9d:ce:77:a9:af:a1:93:
         10:8c:27:48:1a:1f:62:48:04:8f:64:51:6d:52:e9:60:6d:a9:
         98:7b:43:d6:cc:66:69:65:40:d6:57:ff:06:f5:73:59:8f:1b:
         87:9b:36:5b:41:06:4a:5e:25:69:bb:f0:70:49:72:0b:d8:67:
         7b:ed:d4:b3:c8:79:c8:58:5e:f3:f1:f5:98:fa:80:03:d3:7d:
         8a:d0:c8:76
Certificate:
    Data:
        Version: 3 (0x2)
        Serial Number: 146025 (0x23a69)
    Signature Algorithm: sha1WithRSAEncryption
        Issuer: C=US, O=GeoTrust Inc., CN=GeoTrust Global CA
        Validity
            Not Before: Apr  5 15:15:55 2013 GMT
            Not After : Apr  4 15:15:55 2015 GMT
        Subject: C=US, O=Google Inc, CN=Google Internet Authority G2
        Subject Public Key Info:
            Public Key Algorithm: rsaEncryption
                Public-Key: (2048 bit)
                Modulus:
                    00:9c:2a:04:77:5c:d8:50:91:3a:06:a3:82:e0:d8:
                    50:48:bc:89:3f:f1:19:70:1a:88:46:7e:e0:8f:c5:
                    f1:89:ce:21:ee:5a:fe:61:0d:b7:32:44:89:a0:74:
                    0b:53:4f:55:a4:ce:82:62:95:ee:eb:59:5f:c6:e1:
                    05:80:12:c4:5e:94:3f:bc:5b:48:38:f4:53:f7:24:
                    e6:fb:91:e9:15:c4:cf:f4:53:0d:f4:4a:fc:9f:54:
                    de:7d:be:a0:6b:6f:87:c0:d0:50:1f:28:30:03:40:
                    da:08:73:51:6c:7f:ff:3a:3c:a7:37:06:8e:bd:4b:
                    11:04:eb:7d:24:de:e6:f9:fc:31:71:fb:94:d5:60:
                    f3:2e:4a:af:42:d2:cb:ea:c4:6a:1a:b2:cc:53:dd:
                    15:4b:8b:1f:c8:19:61:1f:cd:9d:a8:3e:63:2b:84:
                    35:69:65:84:c8:19:c5:46:22:f8:53:95:be:e3:80:
                    4a:10:c6:2a:ec:ba:97:20:11:c7:39:99:10:04:a0:
                    f0:61:7a:95:25:8c:4e:52:75:e2:b6:ed:08:ca:14:
                    fc:ce:22:6a:b3:4e:cf:46:03:97:97:03:7e:c0:b1:
                    de:7b:af:45:33:cf:ba:3e:71:b7:de:f4:25:25:c2:
                    0d:35:89:9d:9d:fb:0e:11:79:89:1e:37:c5:af:8e:
                    72:69
                Exponent: 65537 (0x10001)
        X509v3 extensions:
            X509v3 Authority Key Identifier:
                keyid:C0:7A:98:68:8D:89:FB:AB:05:64:0C:11:7D:AA:7D:65:B8:CA:CC:4E

            X509v3 Subject Key Identifier:
                4A:DD:06:16:1B:BC:F6:68:B5:76:F5:81:B6:BB:62:1A:BA:5A:81:2F
            X509v3 Basic Constraints: critical
                CA:TRUE, pathlen:0
            X509v3 Key Usage: critical
                Certificate Sign, CRL Sign
            X509v3 CRL Distribution Points:

                Full Name:
                  URI:http://crl.geotrust.com/crls/gtglobal.crl

            Authority Information Access:
                OCSP - URI:http://gtglobal-ocsp.geotrust.com

            X509v3 Certificate Policies:
                Policy: 1.3.6.1.4.1.11129.2.5.1

    Signature Algorithm: sha1WithRSAEncryption
         36:d7:06:80:11:27:ad:2a:14:9b:38:77:b3:23:a0:75:58:bb:
         b1:7e:83:42:ba:72:da:1e:d8:8e:36:06:97:e0:f0:95:3b:37:
         fd:1b:42:58:fe:22:c8:6b:bd:38:5e:d1:3b:25:6e:12:eb:5e:
         67:76:46:40:90:da:14:c8:78:0d:ed:95:66:da:8e:86:6f:80:
         a1:ba:56:32:95:86:dc:dc:6a:ca:04:8c:5b:7f:f6:bf:cc:6f:
         85:03:58:c3:68:51:13:cd:fd:c8:f7:79:3d:99:35:f0:56:a3:
         bd:e0:59:ed:4f:44:09:a3:9e:38:7a:f6:46:d1:1d:12:9d:4f:
         be:d0:40:fc:55:fe:06:5e:3c:da:1c:56:bd:96:51:7b:6f:57:
         2a:db:a2:aa:96:dc:8c:74:c2:95:be:f0:6e:95:13:ff:17:f0:
         3c:ac:b2:10:8d:cc:73:fb:e8:8f:02:c6:f0:fb:33:b3:95:3b:
         e3:c2:cb:68:58:73:db:a8:24:62:3b:06:35:9d:0d:a9:33:bd:
         78:03:90:2e:4c:78:5d:50:3a:81:d4:ee:a0:c8:70:38:dc:b2:
         f9:67:fa:87:40:5d:61:c0:51:8f:6b:83:6b:cd:05:3a:ca:e1:
         a7:05:78:fc:ca:da:94:d0:2c:08:3d:7e:16:79:c8:a0:50:20:
         24:54:33:71
Certificate:
    Data:
        Version: 3 (0x2)
        Serial Number: 1227750 (0x12bbe6)
    Signature Algorithm: sha1WithRSAEncryption
        Issuer: C=US, O=Equifax, OU=Equifax Secure Certificate Authority
        Validity
            Not Before: May 21 04:00:00 2002 GMT
            Not After : Aug 21 04:00:00 2018 GMT
        Subject: C=US, O=GeoTrust Inc., CN=GeoTrust Global CA
        Subject Public Key Info:
            Public Key Algorithm: rsaEncryption
                Public-Key: (2048 bit)
                Modulus:
                    00:da:cc:18:63:30:fd:f4:17:23:1a:56:7e:5b:df:
                    3c:6c:38:e4:71:b7:78:91:d4:bc:a1:d8:4c:f8:a8:
                    43:b6:03:e9:4d:21:07:08:88:da:58:2f:66:39:29:
                    bd:05:78:8b:9d:38:e8:05:b7:6a:7e:71:a4:e6:c4:
                    60:a6:b0:ef:80:e4:89:28:0f:9e:25:d6:ed:83:f3:
                    ad:a6:91:c7:98:c9:42:18:35:14:9d:ad:98:46:92:
                    2e:4f:ca:f1:87:43:c1:16:95:57:2d:50:ef:89:2d:
                    80:7a:57:ad:f2:ee:5f:6b:d2:00:8d:b9:14:f8:14:
                    15:35:d9:c0:46:a3:7b:72:c8:91:bf:c9:55:2b:cd:
                    d0:97:3e:9c:26:64:cc:df:ce:83:19:71:ca:4e:e6:
                    d4:d5:7b:a9:19:cd:55:de:c8:ec:d2:5e:38:53:e5:
                    5c:4f:8c:2d:fe:50:23:36:fc:66:e6:cb:8e:a4:39:
                    19:00:b7:95:02:39:91:0b:0e:fe:38:2e:d1:1d:05:
                    9a:f6:4d:3e:6f:0f:07:1d:af:2c:1e:8f:60:39:e2:
                    fa:36:53:13:39:d4:5e:26:2b:db:3d:a8:14:bd:32:
                    eb:18:03:28:52:04:71:e5:ab:33:3d:e1:38:bb:07:
                    36:84:62:9c:79:ea:16:30:f4:5f:c0:2b:e8:71:6b:
                    e4:f9
                Exponent: 65537 (0x10001)
        X509v3 extensions:
            X509v3 Authority Key Identifier:
                keyid:48:E6:68:F9:2B:D2:B2:95:D7:47:D8:23:20:10:4F:33:98:90:9F:D4

            X509v3 Subject Key Identifier:
                C0:7A:98:68:8D:89:FB:AB:05:64:0C:11:7D:AA:7D:65:B8:CA:CC:4E
            X509v3 Basic Constraints: critical
                CA:TRUE
            X509v3 Key Usage: critical
                Certificate Sign, CRL Sign
            X509v3 CRL Distribution Points:

                Full Name:
                  URI:http://crl.geotrust.com/crls/secureca.crl

            X509v3 Certificate Policies:
                Policy: X509v3 Any Policy
                  CPS: https://www.geotrust.com/resources/repository

    Signature Algorithm: sha1WithRSAEncryption
         76:e1:12:6e:4e:4b:16:12:86:30:06:b2:81:08:cf:f0:08:c7:
         c7:71:7e:66:ee:c2:ed:d4:3b:1f:ff:f0:f0:c8:4e:d6:43:38:
         b0:b9:30:7d:18:d0:55:83:a2:6a:cb:36:11:9c:e8:48:66:a3:
         6d:7f:b8:13:d4:47:fe:8b:5a:5c:73:fc:ae:d9:1b:32:19:38:
         ab:97:34:14:aa:96:d2:eb:a3:1c:14:08:49:b6:bb:e5:91:ef:
         83:36:eb:1d:56:6f:ca:da:bc:73:63:90:e4:7f:7b:3e:22:cb:
         3d:07:ed:5f:38:74:9c:e3:03:50:4e:a1:af:98:ee:61:f2:84:
         3f:12

Other certificate information

You can also retrieve for example the OCSP URL of all certificates:

OLDIFS=$IFS; IFS=':' certificates=$(openssl s_client -connect google.com:443 -showcerts -tlsextdebug 2>&1 </dev/null | sed -n '/-----BEGIN/,/-----END/ {/-----BEGIN/ s/^/:/; p}'); for certificate in ${certificates#:}; do echo $certificate | openssl x509 -noout -ocsp_uri; done; IFS=$OLDIFS

Output:

http://clients1.google.com/ocsp
http://gtglobal-ocsp.geotrust.com

Serial Numbers:

OLDIFS=$IFS; IFS=':' certificates=$(openssl s_client -connect google.com:443 -showcerts -tlsextdebug 2>&1 </dev/null | sed -n '/-----BEGIN/,/-----END/ {/-----BEGIN/ s/^/:/; p}'); for certificate in ${certificates#:}; do echo $certificate | openssl x509 -noout -serial; done; IFS=$OLDIFS

Output:

serial=667966FCE2C7D02D
serial=023A69
serial=12BBE6

The subject in the certificates:

OLDIFS=$IFS; IFS=':' certificates=$(openssl s_client -connect google.com:443 -showcerts -tlsextdebug 2>&1 </dev/null | sed -n '/-----BEGIN/,/-----END/ {/-----BEGIN/ s/^/:/; p}'); for certificate in ${certificates#:}; do echo $certificate | openssl x509 -noout -subject; done; IFS=$OLDIFS

Output:

subject= /C=US/ST=California/L=Mountain View/O=Google Inc/CN=*.google.com
subject= /C=US/O=Google Inc/CN=Google Internet Authority G2
subject= /C=US/O=GeoTrust Inc./CN=GeoTrust Global CA

All the fingerprints:

OLDIFS=$IFS; IFS=':' certificates=$(openssl s_client -connect google.com:443 -showcerts -tlsextdebug 2>&1 </dev/null | sed -n '/-----BEGIN/,/-----END/ {/-----BEGIN/ s/^/:/; p}'); for certificate in ${certificates#:}; do echo $certificate | openssl x509 -noout -subject; echo $certificate | openssl x509 -noout -fingerprint; done; IFS=$OLDIFS

Output:

subject= /C=US/ST=California/L=Mountain View/O=Google Inc/CN=*.google.com
SHA1 Fingerprint=99:00:2C:A4:91:BC:53:D7:53:75:B1:8B:F9:24:55:26:4B:69:A4:34
subject= /C=US/O=Google Inc/CN=Google Internet Authority G2
SHA1 Fingerprint=D8:3C:1A:7F:4D:04:46:BB:20:81:B8:1A:16:70:F8:18:34:51:CA:24
subject= /C=US/O=GeoTrust Inc./CN=GeoTrust Global CA
SHA1 Fingerprint=73:59:75:5C:6D:F9:A0:AB:C3:06:0B:CE:36:95:64:C8:EC:45:42:A3

Sources

Documentation for openssl x509

Tags: articles , bash , certificate , crl , ocsp , sed , shell , ssl , tls