Guide to the Secure Configuration of Oracle Linux 7
Rules, Groups, and Values defined within the XCCDF Benchmark
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Inspect and Activate Default firewalld Rules
Firewalls can be used to separate networks into different zones based on the level of trust the user has decided to place on the devices and traffic within that network. <code>NetworkManager</code>...Group -
Verify firewalld Enabled
Thefirewalld
service can be enabled with the following command:$ sudo systemctl enable firewalld.service
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 configuration files under the <code>/etc/firewalld/services</code> and <code>...Group -
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 line in <code>/etc/sysconfig/ip6tables</code>: <pre...Rule Medium Severity -
Set Default firewalld Zone for Incoming Packets
To set the default zone to <code>drop</code> for the built-in default zone which processes incoming IPv4 and IPv6 packets, modify the following line in <code>/etc/firewalld/firewalld.conf</code> to...Rule Medium Severity -
IPSec Support
Support for Internet Protocol Security (IPsec) is provided with Libreswan.Group -
Install libreswan Package
The libreswan package provides an implementation of IPsec and IKE, which permits the creation of secure tunnels over untrusted networks. The <code>libreswan</code> package can be installed with the...Rule Medium Severity -
Verify Any Configured IPSec Tunnel Connections
Libreswan provides an implementation of IPsec and IKE, which permits the creation of secure tunnels over untrusted networks. As such, IPsec can be used to circumvent certain network requirements su...Rule Medium 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. This firewall is controlled by the program <code...Group -
Install iptables Package
Theiptables
package can be installed with the following command:$ sudo yum install iptables
Rule Medium Severity -
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 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 line in <code>/etc/sysconfig/iptables</code>: <pre>...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 interface to another, add or correct the following line ...Rule Medium Severity -
IPv6
The system includes support for Internet Protocol version 6. A major and often-mentioned improvement over IPv4 is its enormous increase in the number of available addresses. Another important featu...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 address is assigned. The only way to effectively pre...Group -
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/disabled.conf</code> (or another file in <code>/etc/...Rule Medium 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 <code>/etc/modprobe.d</code>. To prevent RPC services ...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 file in <code>/etc/sysctl.d</code>): <pre>net.ipv6....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 another file in <code>/etc/sysctl.d</code>): <pre>n...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 the network. From a security perspective, manually...Group -
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 redirected.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_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 redirected.Value -
net.ipv6.conf.default.autoconf
Enable auto configuration on IPv6 interfacesValue -
net.ipv6.conf.default.max_addresses
Maximum number of autoconfigured IPv6 addressesValue -
net.ipv6.conf.default.router_solicitations
Accept all router solicitations by default?Value -
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 IP as appropriate): <pre>IPV6_DEFAULTGW=...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/ifcfg-<i>interface</i> </code>: <pre>IPV6...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 the following line (substituting the co...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.ipv6.conf.all.accept_ra=0</pre> To make sure that th...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 net.ipv6.conf.all.accept_ra_defrtr=0</pre> To mak...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 net.ipv6.conf.all.accept_ra_pinfo=0</pre> To make ...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 -w net.ipv6.conf.all.accept_ra_rtr_pref=0</pre> To...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 net.ipv6.conf.all.accept_redirects=0</pre> To mak...Rule Medium Severity -
Configure Auto Configuration on All IPv6 Interfaces
To set the runtime status of the <code>net.ipv6.conf.all.autoconf</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w net.ipv6.conf.all.autoconf=0</pre> To make sure that the ...Rule Unknown Severity -
Disable Kernel Parameter for IPv6 Forwarding
To set the runtime status of the <code>net.ipv6.conf.all.forwarding</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w net.ipv6.conf.all.forwarding=0</pre> To make sure that ...Rule Medium Severity -
Configure Maximum Number of Autoconfigured Addresses on All IPv6 Interfaces
To set the runtime status of the <code>net.ipv6.conf.all.max_addresses</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w net.ipv6.conf.all.max_addresses=1</pre> To make sure...Rule Unknown Severity -
Configure Denying Router Solicitations on All IPv6 Interfaces
To set the runtime status of the <code>net.ipv6.conf.all.router_solicitations</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w net.ipv6.conf.all.router_solicitations=0</pre...Rule Unknown Severity -
Disable Accepting Router Advertisements on all IPv6 Interfaces by Default
To set the runtime status of the <code>net.ipv6.conf.default.accept_ra</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w net.ipv6.conf.default.accept_ra=0</pre> To make sure...Rule Medium Severity -
Configure Accepting Default Router in Router Advertisements on All IPv6 Interfaces By Default
To set the runtime status of the <code>net.ipv6.conf.default.accept_ra_defrtr</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w net.ipv6.conf.default.accept_ra_defrtr=0</pre...Rule Unknown Severity -
Configure Accepting Prefix Information in Router Advertisements on All IPv6 Interfaces By Default
To set the runtime status of the <code>net.ipv6.conf.default.accept_ra_pinfo</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w net.ipv6.conf.default.accept_ra_pinfo=0</pre> ...Rule Unknown Severity
Node 2
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