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Ensure ip6tables outbound and established connections are configured
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Based on SOC occupation classification
| name | cis-ubuntu1804-v220-3-4-3-3-3 |
| description | Ensure ip6tables outbound and established connections are configured |
| category | cis-networking |
| version | 2.2.0 |
| author | cyberstrike-official |
| tags | ["cis","ubuntu","linux","ubuntu-18.04","networking","firewall","iptables","ipv6"] |
| cis_id | 3.4.3.3.3 |
| cis_benchmark | CIS Ubuntu Linux 18.04 LTS Benchmark v2.2.0 |
| tech_stack | ["ubuntu","linux"] |
| cwe_ids | [] |
| chains_with | [] |
| prerequisites | [] |
| severity_boost | {} |
Configure the firewall rules for new outbound, and established IPv6 connections.
If rules are not in place for new outbound, and established connections all packets will be dropped by the default policy preventing network usage.
Run the following command and verify all rules for new outbound, and established connections match site policy:
ip6tables -L -v -n
-OR-
Verify IPv6 is disabled: Run the following script. Output will confirm if IPv6 is enabled on the system.
#!/usr/bin/bash
{
if grep -Pqs '^\h*0\b' /sys/module/ipv6/parameters/disable; then
echo -e " - IPv6 is enabled on the system"
else
echo -e " - IPv6 is not enabled on the system"
fi
}
The output should show rules matching site policy for outbound and established IPv6 connections. Or IPv6 is not enabled on the system.
Configure iptables in accordance with site policy. The following commands will implement a policy to allow all outbound connections and all established connections:
ip6tables -A OUTPUT -p tcp -m state --state NEW,ESTABLISHED -j ACCEPT
ip6tables -A OUTPUT -p udp -m state --state NEW,ESTABLISHED -j ACCEPT
ip6tables -A OUTPUT -p icmp -m state --state NEW,ESTABLISHED -j ACCEPT
ip6tables -A INPUT -p tcp -m state --state ESTABLISHED -j ACCEPT
ip6tables -A INPUT -p udp -m state --state ESTABLISHED -j ACCEPT
ip6tables -A INPUT -p icmp -m state --state ESTABLISHED -j ACCEPT
No connection tracking rules exist by default.
Version 8
4.4 Implement and Manage a Firewall on Servers - Implement and manage a firewall on servers, where supported.
4.5 Implement and Manage a Firewall on End-User Devices - Implement and manage a host-based firewall or port-filtering tool on end-user devices.
Version 7
9.4 Apply Host-based Firewalls or Port Filtering - Apply host-based firewalls or port filtering tools on end systems, with a default-deny rule that drops all traffic except those services and ports that are explicitly allowed.
Manual