Guide to the Secure Configuration of Ubuntu 20.04
Rules, Groups, and Values defined within the XCCDF Benchmark
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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 -
authlogin_yubikey SELinux Boolean
default - Default SELinux boolean setting.
on - SELinux boolean is enabled.
off - SELinux boolean is disabled.Value -
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 -
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 -
Verify ufw Enabled
Theufw
service can be enabled with the following command:$ sudo systemctl enable ufw.service
Rule Medium Severity -
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 -
Uninstall nftables package
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 -
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 nftables Rules are Permanent
nftables is a subsystem of the Linux kernel providing filtering and classification of network packets/datagrams/frames. The nftables service reads ...Rule Medium Severity -
Ensure Base Chains Exist 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
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