Title

The RUCKUS ICX perimeter router must be configured to deny network traffic by default and allow network traffic by exception. (Cat I impact)

Discussion

A deny-all, permit-by-exception network communications traffic policy ensures that only connections that are essential and approved are allowed. This requirement applies to both inbound and outbound network communications traffic. All inbound and outbound traffic must be denied by default. Firewalls and perimeter routers should only allow traffic through that is explicitly permitted. The initial defense for the internal network is to block any traffic at the perimeter that is attempting to make a connection to a host residing on the internal network. In addition, allowing unknown or undesirable outbound traffic by the firewall or router will establish a state that will permit the return of this undesirable traffic inbound.

Check Content

Confirm that external interfaces are configured with ACLs that permit traffic by exception. ip access-list extended EXT-ACL sequence 10 permit sshow host x.x.x.x host y.y.y.y log sequence 20 permit ip x.x.x.0 0.0.0.255 any sequence 30 deny ip any any log interface ethernet x/x/x ip access-group EXT-ACL in logging enable If the ACL or filter is not configured to allow specific ports and protocols and deny all other traffic, this is a finding. If the filter is not configured inbound on all external interfaces, this is a finding.

Fix Text

Apply ACL configuration to apply desired traffic restrictions: ip access-list extended EXT-ACL sequence 10 permit sshow host x.x.x.x host y.y.y.y log sequence 20 permit ip x.x.x.0 0.0.0.255 any sequence 30 deny ip any any log interface ethernet x/x/x ip access-group EXT-ACL in logging enable

Additional Identifiers

Rule ID: SV-273604r1110881_rule

Vulnerability ID: V-273604

Group Title: SRG-NET-000202-RTR-000001

Expert Comments

CCIs tied to check.

Controls tied to check. These are derived from the CCIs shown above.