Title

The system must not send IPv4 ICMP redirects. (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 contain information from the system's route table that could reveal portions of the network topology.

Check Content

Determine the type of zone that you are currently securing. # zonename If the zone is not the global zone, determine if any interfaces are exclusive to the zone: # dladm show-link If the output indicates "insufficient privileges" then this requirement is not applicable. If the zone is the global zone or the non-global zone has exclusive interfaces verify the system does not send IPv4 ICMP redirect messages. Procedure: # ndd /dev/ip ip_send_redirects If the result is not 0, this is a finding.

Fix Text

Configure the system to not send IPv4 ICMP redirect messages. Procedure: # ndd -set /dev/ip ip_send_redirects 0 Also add this command to a system startup script.

Additional Identifiers

Rule ID: SV-226898r603265_rule

Vulnerability ID: V-226898

Group Title: SRG-OS-000480

Expert Comments

CCIs tied to check.

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