If you want to find out the components of a site’s certificate the following commands will help you.
If you want to find if the certificate is signed with the weak MD5 signature algorithm:
$ echo | openssl s_client -connect webserver.example.com:443 2>/dev/null | sed -ne ‘/—–BEGIN CERTIFICATE—–/,/—–END CERTIFICATE—–/p’ | openssl x509 -text | grep “Signature Algorithm”| gawk ‘{print $3}’

$ echo | openssl s_client -connect 167.155.38.24:443 2>/dev/null | sed -ne ‘/—–BEGIN CERTIFICATE—–/,/—–END CERTIFICATE—–/p’ | openssl x509 -text | grep “Exponent”