Support Kerberos authentication over SSL

[birk0]

Currently v3.7 of evil-winrm does not support authentication over kerberos when using the -S (ssl) switch when the domain disallows NTLM authentication and forces SSL over port 5986.

evil-winrm -i dc.hades.htb -r hades.htb -u administrator -p 'Password1' -S

2025-09-26 13:02:37 +1000: Warning: User is not needed for Kerberos auth. Ticket will be used
2025-09-26 13:02:37 +1000: Warning: Password is not needed for Kerberos auth. Ticket will be used
2025-09-26 13:02:37 +1000: Error: An error of type ArgumentError happened, message is unknown type: 2916725146
2025-09-26 13:02:37 +1000: Error: Exiting with code 1

In addition omitting password & username, using only the ticket:
evil-winrm -i dc.hades.htb -r hades.htb -S

/var/lib/gems/3.0.0/gems/winrm-2.3.9/lib/winrm/connection_opts.rb:73:in `validate_required_fields': user is a required option (RuntimeError)

My solution when the -S switch is used:

• If $pub_key and $priv_key are provided, certificate authentication is used (no change to existing behavior).
• elseif $realm is specified and no certificate keys are provided, Kerberos authentication is attempted.
• else the connection falls back to NTLM.

example using a valid kerberos ticket over SSL:

klist

Ticket cache: FILE:/tmp/krb5cc_1000
Default principal: administrator@HADES.HTB

Valid starting Expires Service principal
26/09/25 12:40:34 26/09/25 22:40:34 krbtgt/HADES.HTB@HADES.HTB
renew until 27/09/25 12:40:29
26/09/25 12:40:37 26/09/25 22:40:34 HTTP/dc.hades.htb@HADES.HTB
renew until 27/09/25 12:40:29

evil-winrm -i dc.hades.htb -r hades.htb -S