Land #17547, Remove KRB5CCNAME env var on bootup

lib/msf/core/exploit/remote/kerberos/service_authenticator/options.rb

@@ -43,7 +43,7 @@ module Msf::Exploit::Remote::Kerberos::ServiceAuthenticator::Options
       ),
       Msf::OptPath.new(
         "#{protocol}Krb5Ccname",
-        [false, 'The ccache file to use for kerberos authentication', ENV.fetch('SMBKRB5CCNAME', ENV.fetch('KRB5CCNAME', nil))],
+        [false, 'The ccache file to use for kerberos authentication', nil],
         conditions: option_conditions
       )
     ]

lib/msfenv.rb

@@ -7,6 +7,11 @@ ENV['OPENSSL_CONF'] = File.expand_path(
   File.join(File.dirname(__FILE__), '..', 'config', 'openssl.conf')
 )
 
+if ENV['KRB5CCNAME']
+  $stderr.puts 'Warning: KRB5CCNAME environment variable not supported - unsetting'
+  ENV['KRB5CCNAME'] = nil
+end
+
 # Override the normal rails default, so that msfconsole will come up in production mode instead of development mode
 # unless the `--environment` flag is passed.
 ENV['RAILS_ENV'] ||= 'production'