What changed in Cisco IOS Router RTR STIG V3R5V3R5 changes

Check text

This requirement is not applicable for the DODINDOWIN backbone. Step 1: Verify the interface connecting to ISP has an inbound ACL as shown in the example below. interface GigabitEthernet0/2 description Link to ISP ip address x.22.1.15 255.255.255.240 ip access-group FILTER_ISP in Step 2: Verify that the ACL only allows traffic to specific destination addresses (i.e., enclave’s NIPRNet address space) as shown in the example below. ip access-list extended FILTER_ISP permit tcp any any established permit icmp host x.12.1.16 host x.12.1.17 echo permit icmp host x.12.1.16 host x.12.1.17 echo-reply permit tcp any host x.12.1.22 eq www permit tcp any host x.12.1.23 eq www permit 50 any host x.12.1.24 permit 51 any host x.12.1.24 deny ip any any log-input Note: An approved gateway is any external connection from a DODDoW NIPRNet enclave to an internet service provider, network owned by a contractor, or non-DODDoW federal agency that has been approved by either the DODDoW CIO or the DODDoW Component CIO. This approved gateway requirement does not apply to commercial cloud connections when the cloud service provider (CSP) network is connected via the NIPRNet Boundary Cloud Access Point (BCAP). If the ingress ACL bound to the interface connecting to an approved gateway permits packets with addresses other than those specified, such as destination addresses of the site's NIPRNet address space or a destination address belonging to the address block assigned by the approved gateway network service provider, this is a finding.

Fix text

This requirement is not applicable for the DODINDOWIN backbone. Configure the ingress ACL of the perimeter router connected to an approved gateway to only permit packets with destination addresses of the site's NIPRNet address space or a destination address belonging to the address block assigned by the approved gateway network service provider as shown in the example below. R5(config)#ip access-list extended FILTER_ISP R5(config-ext-nacl)#permit tcp any any established R5(config-ext-nacl)#permit icmp host x.12.1.16 host x.12.1.17 echo R5(config-ext-nacl)#permit icmp host x.12.1.16 host x.12.1.17 echo-reply R5(config-ext-nacl)#permit tcp any host x.12.1.22 eq www R5(config-ext-nacl)#permit tcp any host x.12.1.23 eq www R5(config-ext-nacl)#permit 50 any host x.12.1.24 R5(config-ext-nacl)#permit 51 any host x.12.1.24 R5(config-ext-nacl)#deny ip any any log-input R5(config-ext-nacl)#end

Discussion

Enclaves with approved gateway connections must take additional steps to ensure there is no compromise on the enclave network or NIPRNet. Without verifying the destination address of traffic coming from the site's approved gateway, the perimeter router could be routing transit data from the internet into the NIPRNet. This could also make the perimeter router vulnerable to a denial-of-service (DoS) attack and provide a back door into the NIPRNet. The DODDoW enclave must ensure the ingress filter applied to external interfaces on a perimeter router connecting to an approved gateway is secure through filters permitting packets with a destination address belonging to the DODDoW enclave's address block.

V-216576 in V3R5

Title

The Cisco perimeter router must be configured to filter traffic destined to the enclave in accordance with the guidelines contained in DoDW Instruction 8551.1.

Check text

This requirement is not applicable for the DODINDOWIN Backbone. Review the router configuration to verify that the ingress ACL is in accordance with DoDDoW 8551.1. Step 1: Verify that an inbound ACL is configured on all external interfaces. interface GigabitEthernet0/2 ip address x.11.1.2 255.255.255.254 ip access-group EXTERNAL_ACL_INBOUND in Step 2. Review the inbound ACL to verify that it is filtering traffic in accordance with DoDDoW 8551.1. ip access-list extended EXTERNAL_ACL_INBOUND permit tcp any any established permit tcp host x.11.1.1 eq bgp host x.11.1.2 permit tcp host x.11.1.1 host x.11.1.2 eq bgp permit icmp host x.11.1.1 host x.11.1.2 echo permit icmp host x.11.1.1 host x.11.1.2 echo-reply … … &lt must be in accordance with DoDDoW Instruction 8551.1> … deny ip any any log-input If the router does not filter traffic in accordance with the guidelines contained in DoDDoW 8551.1, this is a finding.

Fix text

This requirement is not applicable for the DODINDOWIN Backbone. Configure the router to use an inbound ACL on all external interfaces as shown in the example below to restrict traffic in accordance with the guidelines contained in DODDoW Instruction 8551.1. R1(config)#ip access-list extended EXTERNAL_ACL_INBOUND R1(config-ext-nacl)#permit tcp any any established R1(config-ext-nacl)#permit tcp host x.11.1.1 eq bgp host x.11.1.2 R1(config-ext-nacl)#permit tcp host x.11.1.1 host x.11.1.2 eq bgp R1(config-ext-nacl)#permit icmp host x.11.1.1 host x.11.1.2 echo R1(config-ext-nacl)#permit icmp host x.11.1.1 host x.11.1.2 echo-reply … … &lt must be in accordance with DoDDoW Instruction 8551.1> … R1(config-ext-nacl)#deny ip any any log-input R1(config-ext-nacl)#exit R1(config)#int g0/2 R1(config-if)#ip access-group EXTERNAL_ACL_INBOUND in

V-216580 in V3R5

Discussion

If multicast traffic is forwarded beyond the intended boundary, it is possible that it can be intercepted by unauthorized or unintended personnel. Limiting where, within the network, a given multicast group's data is permitted to flow is an important first step in improving multicast security. A scope zone is an instance of a connected region of a given scope. Zones of the same scope cannot overlap while zones of a smaller scope will fit completely within a zone of a larger scope. For example, Admin-local scope is smaller than Site-local scope, so the administratively configured boundary fits within the bounds of a site. According to RFC 4007 IPv6 Scoped Address Architecture (section 5), scope zones are also required to be "convex from a routing perspective"; that is, packets routed within a zone must not pass through any links that are outside of the zone. This requirement forces each zone to be one contiguous island rather than a series of separate islands. As stated in the DoDDoW IPv6 IA Guidance for MO3, "One should be able to identify all interfaces of a zone by drawing a closed loop on their network diagram, engulfing some routers and passing through some routers to include only some of their interfaces." Therefore, it is imperative that the network engineers have documented their multicast topology and thereby knows which interfaces are enabled for multicast. Once this is done, the zones can be scoped as required.

V-216622 in V3R5