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Check SSL Certificate Chain with OpenSSL Examples

Dovecot and ssl

Networksolutions certs: After creating myserver.key and myserver.csr and obtaining certs: (don't forget to insert newlines between the blocks!)

cat OV_NetworkSolutionsOVServerCA2.crt OV_USERTrustRSACertificationAuthority.crt AddTrustExternalCARoot.crt > intermediate.pem

In dovecot.conf:

ssl_cert_file = /usr/local/etc/IMAP.EXAMPLE.COM.crt
ssl_key_file = /usr/local/etc/myserver.key
#optional, only if you want to require client to provide cert
#ssl_ca_file = /usr/local/etc/intermediate.pem

Courier-imap and ssl

Networksolutions certs: After creating myserver.key and myserver.csr and obtaining certs: (don't forget to insert newlines between the blocks!)

cat AddTrustExternalCARoot.crt NetworkSolutions_CA.crt > intermediate.pem
cat myserver.key >> IMAP.EXAMPLE.COM.crt

In imapd-ssl:

TLS_CERTFILE=/usr/local/etc/courier-certs/IMAP.EXAMPLE.COM.crt
TLS_TRUSTCERTS=/usr/local/etc/courier-certs/intermediate.pem

Network Solutions certificates bundle

See http://blog.irontechsolutions.com/2008/12/10/ssl-chained-certificates-explained/

cat OV_NetworkSolutionsOVServerCA2.crt OV_USERTrustRSACertificationAuthority.crt AddTrustExternalCARoot.crt > intermediate.txt

Comodo bundle order

COMODORSAOrganizationValidationSecureServerCA. + COMODO rsa add trust ca ( + addtrustexternalcaroot )

Generate a signing request

openssl req -nodes -newkey rsa:2048 -keyout my.domain.key -out my.domain.csr

The resulting csr is the signing request, my.domain.key is the private key you save not readable for anyone but root!

HOWTO

Add custom Root CA to your system

On Ubuntu

Copy to /usr/local/share/ca-certificates

update-ca-certificates --fresh

Generate PSK

openssl rand -hex 32

Converting certificates

https://stackoverflow.com/questions/13732826/convert-pem-to-crt-and-key

Create private key (using config file)

openssl req (-config /etc/pki/tls/www.example.com.cnf) -newkey rsa:2048 -nodes -keyout domain.key

Create CSR using config file

openssl req -config /etc/pki/tls/www.example.com.cnf -new -newkey rsa:2048 -nodes -keyout example.com.key -out www.example.com.csr

Create .p12

openssl pkcs12 -export -out keyStore.p12 -inkey myKey.pem -in myCert.cer

Convert der to pem

openssl x509 -inform der -in certificate.cer -out certificate.pem

Creating CSR for multiple hosts

For example http://blog.endpoint.com/2014/10/openssl-csr-with-alternative-names-one.html

Remove password from private key

https://wiki.apache.org/httpd/RemoveSSLCertPassPhrase

Examining certificates

http://www.madboa.com/geek/openssl/#verify-standard

openssl verify cert.pem

openssl x509 -in cacert.pem -noout -text
openssl x509 -in foo.pem  -inform pem -noout -text

openssl rsa -noout -text -in server.key
openssl req -noout -text -in server.csr
openssl rsa -noout -text -in ca.key
openssl x509 -noout -text -in ca.crt

with expiration date:

openssl x509 -noout -text -enddate -in ca.crt

to check CN

openssl x509 -in server.crt -noout -subject

openssl pkcs12 -info -in keyStore.p12
openssl pkcs12 -info -in keyStore.pfx

Checking a service

Note -CApath should point to your local collection of public CA certs

openssl s_client -connect -CApath /etc/ssl/certs host:pop3 -starttls pop3
openssl s_client -port 443 -CApath /etc/ssl/certs -host webmail.example.com -prexit
openssl s_client -connect imap.example.com:143 -starttls imap
openssl s_client -connect web.server:443 -showcerts
openssl s_client -connect webmail.example.com:443 -servername vhost.example.com

Just check expiration date:

 openssl s_client -connect imap.example.com:143 -starttls imap 2>/dev/null | openssl x509 -noout -dates

Check your site

gnutls-cli

echo quit | gnutls-cli --starttls-proto smtp --port 25 servac.skk | grep Status
echo quit | gnutls-cli --port 465 servac.skk | grep Status

check if certs match

TODO: -clr_check too

openssl pkey -in privateKey.key -pubout -outform pem | sha256sum 
openssl x509 -in certificate.crt -pubkey -noout -outform pem | sha256sum 
openssl req -in CSR.csr -pubkey -noout -outform pem | sha256sum

These values show match Also:

openssl verify -CAfile ca-bundle foo_bar.crt

A script to do these checks: [sslcheck]

Creating your own CA and signing with it

(based on http://www.eclectica.ca/howto/ssl-cert-howto.php#rootc)

cd /etc/ssl
mkdir newcerts
(perform secret rituals)

Check which ciphers and tls versions your openssl supports

openssl ciphers -v

Check if site supports TLS v1.2

openssl s_client -connect google.com:443 -servername google.com -tls1_2

FAQ

Error messages

self-signed certificate in certificate chain

OpenSSL: error:0A000102:SSL routines::unsupported protocol

This could becaure you're trying to an older version of TLS, check openssl.cnf for

CipherString = DEFAULT:@SECLEVEL=2

which means it enforces minimum of TLSv1.2

You might now get

OpenSSL: error:0A000152:SSL routines::unsafe legacy renegotiation disabled

which means add below the CipherString line:

Options = UnsafeLegacyRenegotiation

Get issuer

openssl s_client -showcerts -connect <YOURHOST>:443 < /dev/null 2>/dev/null |grep -i issuer

Order of certificates in bundle

Root CA comes last

using s_client

no client certificate sent

try adding -cert

Secure Renegotiation IS NOT supported

Probably using wrong TLS version

Can't use SSL_get_servername

Try using hostname instead of IP address

write:errno=104

server reset the connection

no peer certificate available

Could be trying to talk tls to ssl, also check tls version used/enforced.

unable to load client certificate private key file

Verification error: unable to verify the first certificate

problem missing CA cert

error 20 at 0 depth lookup: unable to get local issuer certificate

you probably need to provide the right -CAfile maybe self signed?

Verify return code: 21 (unable to verify the first certificate)

Probably requires bundle

Bad certificate (code 42)

Means the server demands you authenticate with a certificate, and you did not do so, and that caused the handshake failure.

check certificate chain

openssl s_client -connect www.example.com:443 -showcerts

Some of the output

Certificate chain

0 s:CN = foo.local
  i:CN = foo.local-CA

0: first in chain

s: subject ( openssl x509 -noout -in foo.crt -subject )

i: issuer ( openssl x509 -noout -in foo.crt -issuer )

OR

openssl s_client -showcerts -verify 5 -connect ldap.example.com:636  < /dev/null | awk '/BEGIN/,/END/{ if(/BEGIN/)    {a++}; out="bluePage-cert"a".pem"; print >out}'

or

openssl s_client -showcerts -verify 5 -connect ldap.example.com:389 starttls ldap  < /dev/null | awk '/BEGIN/,/END/{ if(/BEGIN/)    {a++}; out="bluePage-cert"a".pem"; print >out}'

check expiration date

echo | openssl s_client -servername NAME -connect HOST:PORT 2>/dev/null | openssl x509 -noout -dates

openssl x509 -enddate -noout -in file.pem

139814102202256:error:0906D06C:PEM routines:PEM_read_bio:no start line:pem_lib.c:707:Expecting: TRUSTED CERTIFICATE

i've seen this happen when someone deleted the BEGIN/END CERTIFICATE lines

or a file is in DER format

SSL CTX certificate file error: error:0906D06C:PEM routines:PEM_read_bio:no start line

??

check if webserver supports old tls

openssl s_client -connect www.example.com:443 -tls1
openssl s_client -connect www.example.com:443 -tls1_1

or when vhost:

 openssl s_client -servername vhost.example.com -connect www.example.com:443 -tls1_1

ERROR: Certificate verification: Not trusted

seems to be an lftp issue

unsupported certificate purpose

??

ssllabs checks

Chain issues: Incorrect order, Contains anchor

Could be the topmost cert in the bundle provided, try removing it

Chain issues: Contains anchor

Seems to mean there's a root ca in the bundle

check smtp submission

echo -n "username" | base64
echo -n "password" | base64

openssl s_client -connect mail.host.com:587 -starttls smtp -crlf

EHLO foo.bar
AUTH LOGIN

base64username

base64password

OR

echo -ne '\0username\0password'| base64
AUTH LOGIN output_of_that_echo

Peer's Certificate issuer is not recognized.

p12 / pkcs12

Show info about p12 file

openssl pkcs12 -info -in INFILE.p12 -nodes

Extract keys from p12

Extract private key

openssl pkcs12 -in yourP12File.pfx -nocerts -out privateKey.pem

Extract client certificate

openssl pkcs12 -in yourP12File.pfx -clcerts -nokeys -out publicCert.pem

server certificate does NOT include an ID which matches the server name

todo

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