Check: CISC-RT-000236
Cisco NX OS Switch RTR STIG:
CISC-RT-000236
(in versions v2 r3 through v2 r1)
Title
The Cisco switch must be configured to advertise a hop limit of at least 32 in Switch Advertisement messages for IPv6 stateless auto-configuration deployments. (Cat III impact)
Discussion
The Neighbor Discovery protocol allows a hop limit value to be advertised by routers in a Router Advertisement message being used by hosts instead of the standardized default value. If a very small value was configured and advertised to hosts on the LAN segment, communications would fail due to the hop limit reaching zero before the packets sent by a host reached its destination.
Check Content
Review the switch configuration to determine if the hop limit has been configured for Router Advertisement messages for all internal interfaces as shown in the example. interface Ethernet2/1 no switchport ipv6 address 2001::1:0:1/64 ipv6 nd hop-limit 32 no shutdown interface Ethernet2/2 no switchport ipv6 address 2001::1:1:1/64 ipv6 nd hop-limit 32 no shutdown If hop-limit has been configured and has not been set to at least 32, it is a finding.
Fix Text
Configure the switch to advertise a hop limit of at least 32 in Router Advertisement messages as shown in the example. SW1(config)# interface e2/1 – 2 SW1(config-if-range)# ipv6 nd hop-limit 32 SW1(config-if-range)# end
Additional Identifiers
Rule ID: SV-237754r648783_rule
Vulnerability ID: V-237754
Group Title: SRG-NET-000512-RTR-000012
Expert Comments
CCIs
Number | Definition |
---|---|
CCI-000366 |
The organization implements the security configuration settings. |
Controls
Number | Title |
---|---|
CM-6 |
Configuration Settings |