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CIS Ubuntu 20.04 Level 2 Server Benchmark

Rules and Groups employed by this XCCDF Profile

  • 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-persistent Package

    The iptables-persistent package can be installed with the following command:
    $ apt-get install iptables-persistent
    Rule Medium Severity
  • Install iptables Package

    The iptables package can be installed with the following command:
    $ apt-get install iptables
    Rule Medium Severity
  • Remove iptables-persistent Package

    The iptables-persistent package can be removed with the following command:
    $ apt-get remove iptables-persistent
    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
  • 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
  • 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
  • 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
  • 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
  • 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
  • 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
  • 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...
    Rule Medium 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...
    Rule Medium 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.i...
    Rule Medium 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 ne...
    Rule Medium 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 sysct...
    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 sy...
    Rule Medium Severity
  • Kernel Parameters Which Affect Networking

    The <code>sysctl</code> utility is used to set parameters which affect the operation of the Linux kernel. Kernel parameters which affect networking...
    Group
  • Network Related Kernel Runtime Parameters for Hosts and Routers

    Certain kernel parameters should be set for systems which are acting as either hosts or routers to improve the system's ability defend against cert...
    Group
  • 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...
    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...
    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...
    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.ip...
    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...
    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 sysct...
    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 sy...
    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...
    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 ne...
    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 sysct...
    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 ...
    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 s...
    Rule Unknown 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
  • 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 Default Deny Firewall Policy

    Base chain policy is the default verdict that will be applied to packets reaching the end of the chain. There are two policies: accept (Default) an...
    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
  • Set nftables 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
  • 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
  • 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
  • Install ufw Package

    The ufw package can be installed with the following command:
    $ apt-get install ufw
    Rule Medium Severity

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