* Author: Mike Cardwell <sslscanner@grepular.com> https://grepular.com/

sslScanner is an open source Perl application which connects to a range of
hosts/ports which are running SSL based services such as HTTPS. It then displays
the certificate CN and how long is left until the certificate expires. Example:

mike@haven:~$ sslScanner --timeout 5 --expires-within 400 smtp.googlemail.com:465 haven.grepular.com 158.125.1.208/32
     IP Address   Port  Days Left  Input Arg -> Cert Common Name
   74.125.77.16    465        140  smtp.googlemail.com:465 -> smtp.googlemail.com
  92.48.122.147    443        246  haven.grepular.com -> secure.grepular.com
  158.125.1.208    443        358  158.125.1.208/32 -> www.lboro.ac.uk
mike@haven:~$

If you want to be alerted when your certificate has less than 7 days left before
expiry, you might create a simple cron job like this:

@daily sslScanner --expires-within 7 example.com:443

Here are the usage details:

Usage:

1.) sslScanner <Options> <Hosts>
2.) cat Hosts_List.txt | sslScanner <Options>

Hosts:
  Any number of hosts can be scanned. They must each adhere to one of
  the following formats:

  x.x.x.x           : IP address
  x.x.x.x/cidr      : CIDR network. Requires NetAddr::IP
  x.x.x.x:port      : IP address with port
  x.x.x.x/cidr:port : CIDR network and port. Requires NetAddr::IP
  example.com       : Domain name
  example.com:port  : Domain name with port

  The port defaults to 443 (https) if not provided

IPv6/IPv4 notes:
  x.x.x.x in all of the above examples can be replaced with an IPv6 address,
  surrounded by square brackets. By default, we do both IPv6 and IPv4 checks.
  If you use either --ipv4 or --ipv6, then only IPv4 or IPv6 checks will take
  place when a hostname is looked up.

Options:
  --help or -h          : Display this help information and exit
  --ipv6                : Enable IPv6 checks
  --ipv4                : Enable IPv4 checks
  --timeout secs        : Connection timeout. Default is 10
  --expires-within days : Only display info for those certs which
                          expire within x days, or that fail to lookup


Install requirements
--------------------

sudo apt-get install libssl-dev
sudo cpan Crypt::OpenSSL::X509
sudo cpan Net::SSL::ExpireDate
sudo cpan IO::Socket::INET6 (only for IPv6 support)