Rule ID
SV-220419r1195270_rule
Version
V3R3
CCIs
Information flow control regulates where information is allowed to travel within a network and between interconnected networks. The flow of all network traffic must be monitored and controlled so it does not introduce any unacceptable risk to the network infrastructure or data. Information flow control policies and enforcement mechanisms are commonly employed by organizations to control the flow of information between designated sources and destinations (e.g., networks, individuals, and devices) within information systems. Enforcement occurs, for example, in boundary protection devices (e.g., gateways, switches, guards, encrypted tunnels, and firewalls) that employ rule sets or establish configuration settings that restrict information system services, provide a packet-filtering capability based on header information, or provide a message-filtering capability based on message content (e.g., implementing key word searches or using document characteristics).
If Virtual Routing and Forwarding (VRF) is used to segment traffic and force traffic to traverse through next generation firewalls with ACLs, this requirement is not applicable. Review the switch configuration to verify that ACLs are configured to allow or deny traffic for specific source and destination addresses as well as ports and protocols. For example, the configuration below will allow only printer traffic into subnet 10.1.12.0/24 and SQL traffic into subnet 10.1.13.0/24. ICMP is allowed for troubleshooting and OSPF is the routing protocol used within the network. interface GigabitEthernet0/1 no switchport ip address 10.2.1.1 255.255.255.252 ip access-group FILTER_SERVER_TRAFFIC in … … … ip access-list extended FILTER_SERVER_TRAFFIC permit tcp any 10.1.12.0 0.0.0.255 eq lpd 631 9100 permit tcp any 10.1.13.0 0.0.0.255 eq 1433 1434 4022 permit icmp any any permit ospf any any deny ip any any Alternate: Inter-VLAN routing interface Vlan12 ip address 10.1.12.1 255.255.255.0 ip access-group FILTER_PRINTER_VLAN out ! interface Vlan13 ip address 10.1.13.1 255.255.255.0 ip access-group FILTER_SQL_VLAN out … … … ip access-list extended FILTER_PRINTER_VLAN permit tcp any any eq lpd 631 9100 permit icmp any any deny ip any any ip access-list extended FILTER_SQL_VLAN permit tcp any any eq 1433 1434 4022 permit icmp any any deny ip any any If the switch is not configured to enforce approved authorizations for controlling the flow of information within the network based on organization-defined information flow control policies, this is a finding.
Configure ACLs to allow or deny traffic for specific source and destination addresses as well as ports and protocols between various subnets as required. The commands below were used to create the configuration as shown in the check content: SW1(config)#ip access-list extended FILTER_SERVER_TRAFFIC SW1(config-ext-nacl)#permit tcp any 10.1.12.0 0.0.0.255 eq 515 631 9100 SW1(config-ext-nacl)#permit tcp any 10.1.13.0 0.0.0.255 eq 1433 1434 4022 SW1(config-ext-nacl)#permit icmp any any SW1(config-ext-nacl)#permit ospf any any SW1(config-ext-nacl)#deny ip any any SW1(config-ext-nacl)#exit SW1(config)#interface g0/1 SW1(config-if)#ip access-group FILTER_SERVER_TRAFFIC in SW1(config-if)#end Alternate: Inter-VLAN routing SW1(config)#ip access-list extended FILTER_PRINTER_VLAN SW1(config-ext-nacl)#permit tcp any any eq lpd 631 9100 SW1(config-ext-nacl)#permit icmp any any SW1(config-ext-nacl)#deny ip any any SW1(config-ext-nacl)#exit SW1(config)#ip access-list extended FILTER_SQL_VLAN SW1(config-ext-nacl)#permit tcp any any eq 1433 1434 4022 SW1(config-ext-nacl)#permit icmp any any SW1(config-ext-nacl)#deny ip any any SW1(config-ext-nacl)#exit SW1(config)#interface vlan 12 SW1(config-if)#ip access-group FILTER_PRINTER_VLAN out SW1(config-if)#exit SW1(config)#interface vlan 13 SW1(config-if)#ip access-group FILTER_SQL_VLAN out SW1(config-if)#end