Guide to the Secure Configuration of Red Hat Enterprise Linux 8
Rules, Groups, and Values defined within the XCCDF Benchmark
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Configure Kernel to Rate Limit Sending of Duplicate TCP Acknowledgments
Make sure that the system is configured to limit the maximal rate for sending duplicate acknowledgments in response to incoming TCP packets that ar...Rule Medium Severity -
Enable Kernel Parameter to Use TCP RFC 1337 on IPv4 Interfaces
To set the runtime status of the <code>net.ipv4.tcp_rfc1337</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w net.ipv4.tcp_...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.t...Rule Medium Severity -
Network Parameters for Hosts Only
If the system is not going to be used as a router, then setting certain kernel parameters ensure that the host will not perform routing of network ...Group -
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 n...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 ...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_fo...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 guidanc...Group -
Nftables Base Chain Hooks
The possible hooks which can be used to configure the base chain are: <code>ingress</code> (only in netdev family since Linux kernel 4.2, and inet ...Value -
Nftables Chain Names
The rules in nftables are attached to chains. Unlike in iptables, there are no predefined chains like INPUT, OUTPUT, etc. Instead, to filter pack...Value -
Nftables Base Chain Policies
This is the default verdict that will be applied to packets reaching the end of the chain (i.e, no more rules to be evaluated against). Currently ...Value -
Nftables Base Chain Priorities
Each nftables base chain is assigned a priority that defines its ordering among other base chains, flowtables, and Netfilter internal operations a...Value -
Nftables Base Chain Types
Base chains are those that are registered into the Netfilter hooks, i.e. these chains see packets flowing through the Linux TCP/IP stack. The poss...Value -
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, ...Rule Medium Severity -
Nftables Families
Netfilter enables filtering at multiple networking levels. With iptables there is a separate tool for each level: iptables, ip6tables, arptables, ...Value -
Nftables Master configuration file
The file which contains top level configuration for nftables service, and with which, the service is started.Value -
Nftables Tables
Tables in nftables hold chains. Each table only has one address family and only applies to packets of this family. Tables can have one of six fami...Value -
Install nftables Package
nftables provides a new in-kernel packet classification framework that is based on a network-specific Virtual Machine (VM) and a new nft userspace ...Rule Medium Severity -
Verify nftables Service is Enabled
The nftables service allows for the loading of nftables rulesets during boot, or starting on the nftables service The <code>nftables</code> servic...Rule Medium Severity -
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 ipta...Rule Medium Severity -
Ensure a Table Exists for Nftables
Tables in nftables hold chains. Each table only has one address family and only applies to packets of this family. Tables can have one of six famil...Rule Medium Severity -
SuSEfirewall2
The SuSEfirewall2 provides a managed firewall.Group -
Uncomplicated Firewall (ufw)
The Linux kernel in Ubuntu provides a packet filtering system called netfilter, and the traditional interface for manipulating netfilter are the ip...Group -
Verify ufw Enabled
Theufwservice can be enabled with the following command:$ sudo systemctl enable ufw.service
Rule Medium Severity -
Uncommon Network Protocols
The system includes support for several network protocols which are not commonly used. Although security vulnerabilities in kernel networking code ...Group -
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 path...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. T...Rule Medium Severity -
Disable IEEE 1394 (FireWire) Support
The IEEE 1394 (FireWire) is a serial bus standard for high-speed real-time communication. To configure the system to prevent the <code>firewire-co...Rule Low Severity -
Disable RDS Support
The Reliable Datagram Sockets (RDS) protocol is a transport layer protocol designed to provide reliable high-bandwidth, low-latency communications ...Rule Low Severity -
Disable SCTP Support
The Stream Control Transmission Protocol (SCTP) is a transport layer protocol, designed to support the idea of message-oriented communication, with...Rule Medium Severity -
Disable TIPC Support
The Transparent Inter-Process Communication (TIPC) protocol is designed to provide communications between nodes in a cluster. To configure the sys...Rule Low 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 net...Group -
Disable Wireless Through Software Configuration
If it is impossible to remove the wireless hardware from the device in question, disable as much of it as possible through software. The following ...Group -
Disable Bluetooth Service
The <code>bluetooth</code> service can be disabled with the following command: <pre>$ sudo systemctl mask --now bluetooth.service</pre> <pre>$ sud...Rule Medium Severity -
Disable Bluetooth Kernel Module
The kernel's module loading system can be configured to prevent loading of the Bluetooth module. Add the following to the appropriate <code>/etc/mo...Rule Medium Severity -
Disable Kernel cfg80211 Module
To configure the system to prevent the <code>cfg80211</code> kernel module from being loaded, add the following line to the file <code>/etc/modpro...Rule Medium Severity -
Disable Kernel iwlmvm Module
To configure the system to prevent the <code>iwlmvm</code> kernel module from being loaded, add the following line to the file <code>/etc/modprobe...Rule Medium Severity -
Disable Kernel iwlwifi Module
To configure the system to prevent the <code>iwlwifi</code> kernel module from being loaded, add the following line to the file <code>/etc/modprob...Rule Medium Severity -
Disable Kernel mac80211 Module
To configure the system to prevent the <code>mac80211</code> kernel module from being loaded, add the following line to the file <code>/etc/modpro...Rule Medium Severity -
Disable WiFi or Bluetooth in BIOS
Some machines that include built-in wireless support offer the ability to disable the device through the BIOS. This is hardware-specific; consult y...Rule Unknown 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 wire...Rule Medium Severity -
Disable Unused Interfaces
Network interfaces expand the attack surface of the system. Unused interfaces are not monitored or controlled, and should be disabled. <br><br> If...Group -
Transport Layer Security Support
Support for Transport Layer Security (TLS), and its predecessor, the Secure Sockets Layer (SSL), is included in Red Hat Enterprise Linux in the Ope...Group -
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 t...Group -
Verify Permissions on Important Files and Directories
Permissions for many files on a system must be set restrictively to ensure sensitive information is properly protected. This section discusses impo...Group -
Ensure All World-Writable Directories Are Owned by root User
All directories in local partitions which are world-writable should be owned by root. If any world-writable directories are not owned by root, this...Rule Medium Severity -
Ensure All World-Writable Directories Are Owned by a System Account
All directories in local partitions which are world-writable should be owned by root or another system account. If any world-writable directories a...Rule Medium Severity -
Ensure All World-Writable Directories Are Group Owned by a System Account
All directories in local partitions which are world-writable should be group owned by root or another system account. If any world-writable directo...Rule Medium Severity -
Verify Permissions on /etc/audit/auditd.conf
To properly set the permissions of/etc/audit/auditd.conf, run the command:$ sudo chmod 0640 /etc/audit/auditd.conf
Rule Medium Severity -
Verify Permissions on /etc/audit/rules.d/*.rules
To properly set the permissions of/etc/audit/rules.d/*.rules, run the command:$ sudo chmod 0640 /etc/audit/rules.d/*.rules
Rule Medium Severity
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