Guide to the Secure Configuration of Red Hat Enterprise Linux 8
Rules, Groups, and Values defined within the XCCDF Benchmark
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Remove iptables-services Package
Theiptables-services
package can be removed with the following command:$ sudo yum erase iptables-services
Rule Medium Severity -
Inspect and Activate Default Rules
View the currently-enforced <code>iptables</code> rules by running the command: <pre>$ sudo iptables -nL --line-numbers</pre> The command is analog...Group -
Verify ip6tables Enabled if Using IPv6
Theip6tables
service can be enabled with the following command:$ sudo systemctl enable ip6tables.service
Rule Medium Severity -
Verify iptables Enabled
Theiptables
service can be enabled with the following command:$ sudo systemctl enable iptables.service
Rule Medium Severity -
Set Default ip6tables Policy for Incoming Packets
To set the default policy to DROP (instead of ACCEPT) for the built-in INPUT chain which processes incoming packets, add or correct the following l...Rule Medium Severity -
Set configuration for IPv6 loopback traffic
Configure the loopback interface to accept traffic. Configure all other interfaces to deny traffic to the loopback network.Rule Medium Severity -
Set configuration for loopback traffic
Configure the loopback interface to accept traffic. Configure all other interfaces to deny traffic to the loopback network.Rule Medium Severity -
Strengthen the Default Ruleset
The default rules can be strengthened. The system scripts that activate the firewall rules expect them to be defined in the configuration files <co...Group -
Ensure ip6tables Firewall Rules Exist for All Open Ports
Any ports that have been opened on non-loopback addresses need firewall rules to govern traffic.Rule Medium Severity -
Ensure iptables Firewall Rules Exist for All Open Ports
Any ports that have been opened on non-loopback addresses need firewall rules to govern traffic.Rule Medium Severity -
Set Default iptables Policy for Incoming Packets
To set the default policy to DROP (instead of ACCEPT) for the built-in INPUT chain which processes incoming packets, add or correct the following l...Rule Medium Severity -
Set Default iptables Policy for Forwarded Packets
To set the default policy to DROP (instead of ACCEPT) for the built-in FORWARD chain which processes packets that will be forwarded from one interf...Rule Medium Severity -
Restrict ICMP Message Types
In <code>/etc/sysconfig/iptables</code>, the accepted ICMP messages types can be restricted. To accept only ICMP echo reply, destination unreachabl...Group -
Log and Drop Packets with Suspicious Source Addresses
Packets with non-routable source addresses should be rejected, as they may indicate spoofing. Because the modified policy will reject non-matching ...Group -
IPv6
The system includes support for Internet Protocol version 6. A major and often-mentioned improvement over IPv4 is its enormous increase in the numb...Group -
Disable Support for IPv6 Unless Needed
Despite configuration that suggests support for IPv6 has been disabled, link-local IPv6 address auto-configuration occurs even when only an IPv4 ad...Group -
Ensure IPv6 is disabled through kernel boot parameter
To disable IPv6 protocol support in the Linux kernel, add the argument <code>ipv6.disable=1</code> to the default GRUB2 command line for the Linux ...Rule Low Severity -
Disable IPv6 Networking Support Automatic Loading
To prevent the IPv6 kernel module (<code>ipv6</code>) from binding to the IPv6 networking stack, add the following line to <code>/etc/modprobe.d/di...Rule Medium Severity -
Disable Interface Usage of IPv6
To disable interface usage of IPv6, add or correct the following lines in <code>/etc/sysconfig/network</code>: <pre>NETWORKING_IPV6=no IPV6INIT=no<...Rule Unknown Severity -
Disable Support for RPC IPv6
RPC services for NFSv4 try to load transport modules for <code>udp6</code> and <code>tcp6</code> by default, even if IPv6 has been disabled in <cod...Rule Unknown Severity -
Disable IPv6 Addressing on All IPv6 Interfaces
To disable support for (<code>ipv6</code>) addressing on all interface add the following line to <code>/etc/sysctl.d/ipv6.conf</code> (or another f...Rule Medium Severity -
Disable IPv6 Addressing on IPv6 Interfaces by Default
To disable support for (<code>ipv6</code>) addressing on interfaces by default add the following line to <code>/etc/sysctl.d/ipv6.conf</code> (or a...Rule Medium Severity -
Configure IPv6 Settings if Necessary
A major feature of IPv6 is the extent to which systems implementing it can automatically configure their networking devices using information from ...Group -
IPV6_AUTOCONF
Toggle global IPv6 auto-configuration (only, if global forwarding is disabled)Value -
net.ipv6.conf.all.accept_ra_defrtr
Accept default router in router advertisements?Value -
net.ipv6.conf.all.accept_ra_pinfo
Accept prefix information in router advertisements?Value -
net.ipv6.conf.all.accept_ra_rtr_pref
Accept router preference in router advertisements?Value -
net.ipv6.conf.all.accept_ra
Accept all router advertisements?Value -
net.ipv6.conf.all.accept_redirects
Toggle ICMP Redirect AcceptanceValue -
net.ipv6.conf.all.accept_source_route
Trackers could be using source-routed packets to generate traffic that seems to be intra-net, but actually was created outside and has been redirec...Value -
net.ipv6.conf.all.autoconf
Enable auto configuration on IPv6 interfacesValue -
net.ipv6.conf.all.forwarding
Toggle IPv6 ForwardingValue -
net.ipv6.conf.all.max_addresses
Maximum number of autoconfigured IPv6 addressesValue -
net.ipv6.conf.all.router_solicitations
Accept all router solicitations?Value -
net.ipv6.conf.default.accept_ra_defrtr
Accept default router in router advertisements?Value -
net.ipv6.conf.default.accept_ra_pinfo
Accept prefix information in router advertisements?Value -
net.ipv6.conf.default.accept_ra_rtr_pref
Accept router preference in router advertisements?Value -
net.ipv6.conf.default.accept_ra
Accept default router advertisements by default?Value -
net.ipv6.conf.default.accept_redirects
Toggle ICMP Redirect Acceptance By DefaultValue -
net.ipv6.conf.default.accept_source_route
Trackers could be using source-routed packets to generate traffic that seems to be intra-net, but actually was created outside and has been redirec...Value -
net.ipv6.conf.default.autoconf
Enable auto configuration on IPv6 interfacesValue -
net.ipv6.conf.default.forwarding
Toggle IPv6 default ForwardingValue -
Manually Assign IPv6 Router Address
Edit the file <code>/etc/sysconfig/network-scripts/ifcfg-<i>interface</i></code>, and add or correct the following line (substituting your gateway ...Rule Unknown Severity -
Use Privacy Extensions for Address
To introduce randomness into the automatic generation of IPv6 addresses, add or correct the following line in <code>/etc/sysconfig/network-scripts/...Rule Unknown Severity -
Manually Assign Global IPv6 Address
To manually assign an IP address for an interface, edit the file <code>/etc/sysconfig/network-scripts/ifcfg-<i>interface</i></code>. Add or correct...Rule Unknown Severity -
Configure Accepting Router Advertisements on All IPv6 Interfaces
To set the runtime status of the <code>net.ipv6.conf.all.accept_ra</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w net.ip...Rule Medium Severity -
Configure Accepting Default Router in Router Advertisements on All IPv6 Interfaces
To set the runtime status of the <code>net.ipv6.conf.all.accept_ra_defrtr</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w...Rule Unknown Severity -
Configure Accepting Prefix Information in Router Advertisements on All IPv6 Interfaces
To set the runtime status of the <code>net.ipv6.conf.all.accept_ra_pinfo</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w ...Rule Unknown Severity -
Configure Accepting Router Preference in Router Advertisements on All IPv6 Interfaces
To set the runtime status of the <code>net.ipv6.conf.all.accept_ra_rtr_pref</code> kernel parameter, run the following command: <pre>$ sudo sysctl ...Rule Unknown Severity -
Disable Accepting ICMP Redirects for All IPv6 Interfaces
To set the runtime status of the <code>net.ipv6.conf.all.accept_redirects</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w...Rule Medium Severity
Node 2
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