Important note The guide bellow instructs how to secure Cisco Firewall (PIX, ASA, FWSM). Not all commands will work on every device series or on every IOS version. It is highly recommended to test each setting in a test lab before implementing changes to production systems.
Hardening phase Configure AAA Authentication for Enable Mode (ASA, FWSM, PIX): aaa authentication enable console LOCAL
Configure AAA Authentication for Console and VTY Lines (ASA, FWSM, PIX): aaa authentication serial console LOCAL aaa authentication ssh console LOCAL aaa authentication http console LOCAL
Configure Local Password (ASA, FWSM, PIX): passwd <login_password> encrypted
Configure ASDM Access Control (ASA, FWSM, PIX): **_http <remote_ip_address> <remote_subnet_mask> <interface_name>_****
Configuring SSH (ASA, FWSM, PIX): hostname <device_hostname> domain-name <domain-name> crypto key generate rsa modulus 2048
Configure SSH for Remote Device Access (ASA, PIX): no telnet 0.0.0.0 0.0.0.0 <interface_name> ssh <remote_ip_address> <remote_subnet_mask> <interface_name> ssh version 2
Configure Timeout for Login Sessions (ASA, FWSM, PIX): console timeout 10 ssh timeout 10
Configure Local User and Encrypted Password (ASA, FWSM, PIX): username <local_username> password <local_password> encrypted
Configure Enable Password (ASA, FWSM, PIX): enable password <enable_password> encrypted
Disable SNMP Read Access (ASA, FWSM, PIX): clear configure snmp-server no snmp-server host <interface_name> <remote_ip_address>
Disable SNMP Traps (ASA, FWSM, PIX): no snmp-server enable traps all
Configure Clock Time Zone (ASA, PIX): clock timezone GMT <hours offset>
Disable DHCP Server Service (ASA, FWSM, PIX): clear configure dhcpd no dhcpd enable <interface_name>
Disable HTTP Service (ASA, FWSM, PIX) - in-case not in use: no http server enable <port>
Configure Console Logging Severity Level (ASA, FWSM, PIX): logging console critical
Configure Timestamps in Log Messages (ASA, FWSM, PIX): logging timestamp
Configure AAA Flood Guard (FWSM, PIX): floodguard enable
Configure Fragment Chain Fragmentation Checks (ASA, FWSM, PIX): fragment chain 1 <interface_name>
Configure Protocol Inspection (FWSM, PIX): fixup protocol ftp <port> fixup protocol http <port> fixup protocol smtp <port>
Configure Protocol Inspection (ASA): inspect ftp [map_name] inspect http [map_name] inspect esmtp [map_name]
Configure Unicast Reverse-Path Forwarding (ASA, FWSM, PIX): interface <interface_id> ip verify reverse-path interface <interface_name> exit
Save the changes: wr**