The Arista Multilayer Switch must protect an enclave connected to an Alternate Gateway by using an inbound filter that only permits packets with destination addresses within the sites address space.
An XCCDF Rule
Description
Enclaves with Alternate 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 Alternate 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 DoS attack as well as provide a backdoor into the NIPRNet. The DoD 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 DoD enclave's address block.
- ID
- SV-75355r1_rule
- Version
- AMLS-L3-000150
- Severity
- Medium
- References
- Updated
Remediation Templates
A Manual Procedure
Configure the ingress filter of the perimeter router connected to an Alternate 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 Alternate Gateway network service provider. To configure an example of such a statement, enter:
ip access-list [name]
permit ip [source] [destination]
exit
interface [router interface]