Title

The system must ignore IPv6 ICMP redirect messages. (Cat II impact)

Discussion

ICMP redirect messages are used by routers to inform hosts that a more direct route exists for a particular destination. These messages modify the host's route table and are unauthenticated. An illicit ICMP redirect message could result in a man-in-the-middle attack.

Check Content

Verify the system is configured to ignore IPv6 ICMP redirect messages. # ndd /dev/ip6 ip6_ignore_redirect If the returned value is not 1, this is a finding.

Fix Text

Configure the system to ignore IPv6 ICMP redirect messages. # ndd -set /dev/ip6 ip6_ignore_redirect 1 Also add this command to a system startup script.

Additional Identifiers

Rule ID: SV-26937r1_rule

Vulnerability ID: V-22550

Group Title:

Expert Comments

CCIs tied to check.

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