Title

The Cisco ACI must not be configured to use IPv6 site local unicast addresses. (Cat II impact)

Discussion

As currently defined, site local addresses are ambiguous and can be present in multiple sites. The address itself does not contain any indication of the site to which it belongs. The use of site-local addresses has the potential to adversely affect network security through leaks, ambiguity, and potential misrouting as documented in section 2 of RFC3879. RFC3879 formally deprecates the IPv6 site-local unicast prefix FEC0::/10 as defined in RFC3513. Specify the appropriate IPv6 address range within the relevant configuration objects like bridge domains and L3Out, ensuring the addresses fall within the allocated site local unicast prefix, and enable IPv6 routing on the fabric level, allowing the ACI switches to learn and route traffic based on these IPv6 addresses.

Check Content

Review the router configuration to ensure FEC0::/10 IP addresses are not defined. apic1(config) show ipv6 interface gigabitethernet 0/0/0 If IPv6 site local unicast addresses are defined, this is a finding.

Fix Text

Delete unauthorized addresses. Configure the IPv6 addresses on the ACI fabric's leaf switches and virtual network segments (bridge domains) within the desired tenant to use site local unicast addresses. ipv6 unicast-routing interface gigabitethernet 0/0/0 ipv6 address 2001:DB8:c18:1::/64 eui-64

Additional Identifiers

Rule ID: SV-272101r1064504_rule

Vulnerability ID: V-272101

Group Title: SRG-NET-000512-RTR-000013

Expert Comments

CCIs tied to check.

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