Internet connectivity because of WannaCry attack

[Problem Description]

               Traffic instability; traffic only for seconds after resetting the nat session

[Problem Analysis]

                Topology is very simple: FAT AP doing nat and connected directly to the service provider with public IP

                Check NAT session all

                Traffic succeeded just after reset the nat session and then failed

               when display nat session all

                Noticed that a lot of sessions created in no time to destination port 445 139; which is known for the WannaCry attack

[solution description]

               NAT does not allow the port 445 and 139 as below

              ACL 3000

              rule 10 deny tcp destination-port 139

             rule 20 deny tcp destination-port 445

             rule 30 permit

             int g0/0/1

             NAT outbound acl 3000