Title

The system must not accept source-routed IPv4 packets. (Cat II impact)

Discussion

Source-routed packets allow the source of the packet to suggest routers forward the packet along a different path than configured on the router, which can be used to bypass network security measures. This requirement applies only to the handling of source-routed traffic destined to the system itself, not to traffic forwarded by the system to another, such as when IPv4 forwarding is enabled and the system is functioning as a router.

Check Content

Check the system for an IP Filter (IPF) rule blocking incoming source-routed packets. # ipfstat -i Examine the list for rules such as: block in log quick all with opt lsrr block in log quick all with opt ssrr If the listed rules do not block incoming traffic with both lsrr and ssrr options, this is a finding.

Fix Text

Edit /etc/opt/ipf/ipf.conf and add rules to block incoming source-routed packets, such as: block in log quick all with opt lsrr block in log quick all with opt ssrr Reload the IPF rules. # ipf -Fa -A -f /etc/opt/ipf/ipf.conf

Additional Identifiers

Rule ID: SV-29713r1_rule

Vulnerability ID: V-22414

Group Title: GEN003607

Expert Comments

CCIs tied to check.

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