The system must not have 6to4 enabled.

From Oracle Linux 5 Security Technical Implementation Guide

Associated with: CCI-001551

SV-63423r1_rule The system must not have 6to4 enabled.

Vulnerability discussion

6to4 is an IPv6 transition mechanism involving tunneling IPv6 packets encapsulated in IPv4 packets on an ad-hoc basis. This is not a preferred transition strategy and increases the attack surface of the system.

Check content

Check the system for any active 6to4 tunnels without specific remote addresses. # ip tun list | grep "remote any" | grep "ipv6/ip" If any results are returned the "tunnel" is the first field. If any results are returned, this is a finding.

Fix text

Disable the active 6to4 tunnel. # ip link set down Add this command to a startup script, or remove the configuration creating the tunnel.

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