Guide to the Secure Configuration of Fedora
Rules, Groups, and Values defined within the XCCDF Benchmark
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Install firewalld Package
Thefirewalldpackage can be installed with the following command:$ sudo dnf install firewalld
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 -
Install iptables Package
Theiptablespackage can be installed with the following command:$ sudo dnf install iptables
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 analogous for <code>ip6tables</code>. <br> <br> ...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 operating system. Configure the default Grub2 kern...Rule Low Severity -
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 -
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 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 -
Disable Kernel Parameter for Accepting Source-Routed Packets on all IPv6 Interfaces
To set the runtime status of the <code>net.ipv6.conf.all.accept_source_route</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w net.ipv6.conf.all.accept_source_route=0</pre> ...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 -
Disable Kernel Parameter for Accepting ICMP Redirects by Default on IPv6 Interfaces
To set the runtime status of the <code>net.ipv6.conf.default.accept_redirects</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w net.ipv6.conf.default.accept_redirects=0</pre...Rule Medium Severity -
Disable Kernel Parameter for Accepting Source-Routed Packets on IPv6 Interfaces by Default
To set the runtime status of the <code>net.ipv6.conf.default.accept_source_route</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w net.ipv6.conf.default.accept_source_route=...Rule Medium Severity -
Disable Accepting Packets Routed Between Local Interfaces
To set the runtime status of the <code>net.ipv4.conf.all.accept_local</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w net.ipv4.conf.all.accept_local=0</pre> To make sure t...Rule Medium Severity -
Disable Accepting ICMP Redirects for All IPv4 Interfaces
To set the runtime status of the <code>net.ipv4.conf.all.accept_redirects</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w net.ipv4.conf.all.accept_redirects=0</pre> To mak...Rule Medium Severity -
Disable Kernel Parameter for Accepting Source-Routed Packets on all IPv4 Interfaces
To set the runtime status of the <code>net.ipv4.conf.all.accept_source_route</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w net.ipv4.conf.all.accept_source_route=0</pre> ...Rule Medium Severity -
Configure ARP filtering for All IPv4 Interfaces
To set the runtime status of the <code>net.ipv4.conf.all.arp_filter</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w net.ipv4.conf.all.arp_filter=<xccdf-1.2:sub idref="xccd...Rule Medium Severity -
Configure Response Mode of ARP Requests for All IPv4 Interfaces
To set the runtime status of the <code>net.ipv4.conf.all.arp_ignore</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w net.ipv4.conf.all.arp_ignore=<xccdf-1.2:sub idref="xccd...Rule Medium Severity -
Drop Gratuitious ARP frames on All IPv4 Interfaces
To set the runtime status of the <code>net.ipv4.conf.all.drop_gratuitous_arp</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w net.ipv4.conf.all.drop_gratuitous_arp=1</pre> ...Rule Medium Severity -
Enable Kernel Parameter to Log Martian Packets on all IPv4 Interfaces
To set the runtime status of the <code>net.ipv4.conf.all.log_martians</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w net.ipv4.conf.all.log_martians=1</pre> To make sure t...Rule Unknown Severity -
Enable Kernel Parameter to Use Reverse Path Filtering on all IPv4 Interfaces
To set the runtime status of the <code>net.ipv4.conf.all.rp_filter</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w net.ipv4.conf.all.rp_filter=1</pre> To make sure that th...Rule Medium Severity -
Disable Kernel Parameter for Accepting Secure ICMP Redirects on all IPv4 Interfaces
To set the runtime status of the <code>net.ipv4.conf.all.secure_redirects</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w net.ipv4.conf.all.secure_redirects=0</pre> To mak...Rule Medium Severity -
Configure Sending and Accepting Shared Media Redirects for All IPv4 Interfaces
To set the runtime status of the <code>net.ipv4.conf.all.shared_media</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w net.ipv4.conf.all.shared_media=<xccdf-1.2:sub idref="...Rule Medium Severity -
Disable Kernel Parameter for Accepting ICMP Redirects by Default on IPv4 Interfaces
To set the runtime status of the <code>net.ipv4.conf.default.accept_redirects</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w net.ipv4.conf.default.accept_redirects=0</pre...Rule Medium Severity -
Disable Kernel Parameter for Accepting Source-Routed Packets on IPv4 Interfaces by Default
To set the runtime status of the <code>net.ipv4.conf.default.accept_source_route</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w net.ipv4.conf.default.accept_source_route=...Rule Medium Severity -
Enable Kernel Paremeter to Log Martian Packets on all IPv4 Interfaces by Default
To set the runtime status of the <code>net.ipv4.conf.default.log_martians</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w net.ipv4.conf.default.log_martians=1</pre> To mak...Rule Unknown Severity -
Enable Kernel Parameter to Use Reverse Path Filtering on all IPv4 Interfaces by Default
To set the runtime status of the <code>net.ipv4.conf.default.rp_filter</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w net.ipv4.conf.default.rp_filter=1</pre> To make sure...Rule Medium Severity -
Configure Kernel Parameter for Accepting Secure Redirects By Default
To set the runtime status of the <code>net.ipv4.conf.default.secure_redirects</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w net.ipv4.conf.default.secure_redirects=0</pre...Rule Medium Severity -
Configure Sending and Accepting Shared Media Redirects by Default
To set the runtime status of the <code>net.ipv4.conf.default.shared_media</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w net.ipv4.conf.default.shared_media=<xccdf-1.2:sub...Rule Medium Severity -
Enable Kernel Parameter to Ignore ICMP Broadcast Echo Requests on IPv4 Interfaces
To set the runtime status of the <code>net.ipv4.icmp_echo_ignore_broadcasts</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w net.ipv4.icmp_echo_ignore_broadcasts=1</pre> To...Rule Medium Severity -
Enable Kernel Parameter to Ignore Bogus ICMP Error Responses on IPv4 Interfaces
To set the runtime status of the <code>net.ipv4.icmp_ignore_bogus_error_responses</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w net.ipv4.icmp_ignore_bogus_error_response...Rule Unknown Severity -
Set Kernel Parameter to Increase Local Port Range
To set the runtime status of the <code>net.ipv4.ip_local_port_range</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w net.ipv4.ip_local_port_range=32768 65535</pre> To make ...Rule Medium Severity -
Enable Kernel Parameter to Use TCP Syncookies on Network Interfaces
To set the runtime status of the <code>net.ipv4.tcp_syncookies</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w net.ipv4.tcp_syncookies=1</pre> To make sure that the settin...Rule Medium Severity -
Disable Kernel Parameter for Sending ICMP Redirects on all IPv4 Interfaces
To set the runtime status of the <code>net.ipv4.conf.all.send_redirects</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w net.ipv4.conf.all.send_redirects=0</pre> To make su...Rule Medium Severity -
Disable Kernel Parameter for Sending ICMP Redirects on all IPv4 Interfaces by Default
To set the runtime status of the <code>net.ipv4.conf.default.send_redirects</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w net.ipv4.conf.default.send_redirects=0</pre> To...Rule Medium Severity -
Disable Kernel Parameter for IP Forwarding on IPv4 Interfaces
To set the runtime status of the <code>net.ipv4.ip_forward</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w net.ipv4.ip_forward=0</pre> To make sure that the setting is per...Rule Medium Severity -
nftables
<code>If firewalld or iptables are being used in your environment, please follow the guidance in their respective section and pass-over the guidance in this section.</code><br><br> nftables is a su...Group -
Verify nftables Service is Disabled
nftables is a subsystem of the Linux kernel providing filtering and classification of network packets/datagrams/frames and is the successor to iptables. The <code>nftables</code> service can be dis...Rule Medium Severity -
Verify ufw Enabled
Theufwservice can be enabled with the following command:$ sudo systemctl enable ufw.service
Rule Medium Severity -
Disable ATM Support
The Asynchronous Transfer Mode (ATM) is a protocol operating on network, data link, and physical layers, based on virtual circuits and virtual paths. To configure the system to prevent the <code>a...Rule Medium Severity -
Disable CAN Support
The Controller Area Network (CAN) is a serial communications protocol which was initially developed for automotive and is now also used in marine, industrial, and medical applications. To configur...Rule Medium Severity -
Disable DCCP Support
The Datagram Congestion Control Protocol (DCCP) is a relatively new transport layer protocol, designed to support streaming media and telephony. To configure the system to prevent the <code>dccp</...Rule Medium Severity -
Wireless Networking
Wireless networking, such as 802.11 (WiFi) and Bluetooth, can present a security risk to sensitive or classified systems and networks. Wireless networking hardware is much more likely to be include...Group -
Disable Bluetooth Service
Thebluetoothservice can be disabled with the following command:$ sudo systemctl mask --now bluetooth.service
$ sudo service bluetooth stop
Rule Medium Severity -
Deactivate Wireless Network Interfaces
Deactivating wireless network interfaces should prevent normal usage of the wireless capability. <br> <br> Configure the system to disable all wireless network interfaces with the followi...Rule Medium Severity -
File Permissions and Masks
Traditional Unix security relies heavily on file and directory permissions to prevent unauthorized users from reading or modifying files to which they should not have access. <br> <br> Severa...Group -
Verify that All World-Writable Directories Have Sticky Bits Set
When the so-called 'sticky bit' is set on a directory, only the owner of a given file may remove that file from the directory. Without the sticky bit, any user with write access to a directory may ...Rule Medium Severity -
Verify Permissions on System.map Files
The System.map files are symbol map files generated during the compilation of the Linux kernel. They contain the mapping between kernel symbols and their corresponding memory addresses. In general,...Rule Low Severity -
Ensure All Files Are Owned by a Group
If any file is not group-owned by a group present in /etc/group, the cause of the lack of group-ownership must be investigated. Following this, those files should be deleted or assigned to an appro...Rule Medium Severity -
Enable Kernel Parameter to Enforce DAC on Hardlinks
To set the runtime status of the <code>fs.protected_hardlinks</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w fs.protected_hardlinks=1</pre> To make sure that the setting ...Rule Medium Severity
Node 2
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