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Guide to the Secure Configuration of Red Hat Enterprise Linux 7

Rules, Groups, and Values defined within the XCCDF Benchmark

  • 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
  • iptables and ip6tables

    A host-based firewall called <code>netfilter</code> is included as part of the Linux kernel distributed with the system. It is activated by default...
    Group
  • Install iptables Package

    The iptables package can be installed with the following command:
    $ sudo yum install iptables
    Rule Medium Severity
  • Remove iptables-services Package

    The iptables-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

    The ip6tables service can be enabled with the following command:
    $ sudo systemctl enable ip6tables.service
    Rule Medium Severity
  • Verify iptables Enabled

    The iptables 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
  • 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
  • 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
  • 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 Acceptance
    Value
  • 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 interfaces
    Value
  • net.ipv6.conf.all.forwarding

    Toggle IPv6 Forwarding
    Value
  • net.ipv6.conf.all.max_addresses

    Maximum number of autoconfigured IPv6 addresses
    Value
  • 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 Default
    Value
  • 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 interfaces
    Value
  • net.ipv6.conf.default.forwarding

    Toggle IPv6 default Forwarding
    Value
  • 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

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