fix host validation

host validation was buggy, fixed it

lib/metasploit/framework/login_scanner/ssh.rb

@@ -57,7 +57,6 @@ module Metasploit
           inclusion: { in: [:debug, :info, :warn, :error, :fatal] }
 
         validates :stop_on_success,
-          presence: true,
           inclusion: { in: [true, false] }
 
         validates :host, presence: true
@@ -140,7 +139,7 @@ module Metasploit
               'USERNAME'      => user,
               'PASSWORD'      => pass
           }
-          
+
           session = Msf::Sessions::CommandShell.new(conn.lsock)
           session.info = "SSH: #{user}:#{pass} (#{host}:#{port})"
 
@@ -202,7 +201,12 @@ module Metasploit
             errors.add(:host, "must be a string")
           end
           begin
-            ::Rex::Socket.getaddress(value, true)
+            ::Rex::Socket.getaddress(host, true)
+            if host =~ /^\d{1,3}(\.\d{1,3}){1,3}$/
+              unless host =~ Rex::Socket::MATCH_IPV4
+                errors.add(:host, "could not be resolved")
+              end
+            end
           rescue
             errors.add(:host, "could not be resolved")
           end