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Guide to the Secure Configuration of OpenEmbedded

Rules, Groups, and Values defined within the XCCDF Benchmark

  • Ensure System Log Files Have Correct Permissions

    The file permissions for all log files written by <code>rsyslog</code> should be set to 640, or more restrictive. These log files are determined by...
    Rule Medium Severity
  • systemd-journald

    systemd-journald is a system service that collects and stores logging data. It creates and maintains structured, indexed journals based on logging ...
    Group
  • Enable systemd-journald Service

    The <code>systemd-journald</code> service is an essential component of systemd. The <code>systemd-journald</code> service can be enabled with the ...
    Rule Medium Severity
  • Ensure journald is configured to compress large log files

    The journald system can compress large log files to avoid fill the system disk.
    Rule Medium Severity
  • Ensure journald is configured to send logs to rsyslog

    Data from journald may be stored in volatile memory or persisted locally. Utilities exist to accept remote export of journald logs.
    Rule Medium Severity
  • Ensure journald is configured to write log files to persistent disk

    The journald system may store log files in volatile memory or locally on disk. If the logs are only stored in volatile memory they will we lost upo...
    Rule Medium Severity
  • Ensure All Logs are Rotated by logrotate

    Edit the file <code>/etc/logrotate.d/syslog</code>. Find the first line, which should look like this (wrapped for clarity): <pre>/var/log/message...
    Group
  • Ensure logrotate is Installed

    logrotate is installed by default. The <code>logrotate</code> package can be installed with the following command: <pre> $ sudo dnf install logrota...
    Rule Medium Severity
  • Rsyslog Logs Sent To Remote Host

    If system logs are to be useful in detecting malicious activities, it is necessary to send logs to a remote server. An intruder who has compromised...
    Group
  • Remote Log Server

    Specify an URI or IP address of a remote host where the log messages will be sent and stored.
    Value
  • Ensure Logs Sent To Remote Host

    To configure rsyslog to send logs to a remote log server, open <code>/etc/rsyslog.conf</code> and read and understand the last section of the file,...
    Rule Medium Severity
  • Network Configuration and Firewalls

    Most systems must be connected to a network of some sort, and this brings with it the substantial risk of network attack. This section discusses th...
    Group
  • firewalld

    The dynamic firewall daemon <code>firewalld</code> provides a dynamically managed firewall with support for network “zones” to assign a level of tr...
    Group
  • 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 traffi...
    Group
  • Install firewalld Package

    The firewalld package can be installed with the following command:
    $ sudo dnf install firewalld
    Rule Medium Severity
  • Verify firewalld Enabled

    The firewalld service can be enabled with the following command:
    $ sudo systemctl enable firewalld.service
    Rule Medium Severity
  • Allow IMAP Clients to Access the Server

    The default iptables configuration does not allow inbound access to any services. This modification will allow remote hosts to initiate connection...
    Group
  • 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 Package

    The iptables package 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 analog...
    Group
  • Verify ip6tables Enabled if Using IPv6

    The ip6tables service can be enabled with the following command:
    $ sudo systemctl enable ip6tables.service
    Rule Medium Severity
  • Verify iptables Enabled

    The iptables service can be enabled with the following command:
    $ sudo systemctl enable iptables.service
    Rule Medium Severity
  • 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
  • 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
  • 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 interf...
    Rule Medium Severity
  • Restrict ICMP Message Types

    In <code>/etc/sysconfig/iptables</code>, the accepted ICMP messages types can be restricted. To accept only ICMP echo reply, destination unreachabl...
    Group
  • Log and Drop Packets with Suspicious Source Addresses

    Packets with non-routable source addresses should be rejected, as they may indicate spoofing. Because the modified policy will reject non-matching ...
    Group
  • 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
  • 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 ad...
    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/di...
    Rule Medium 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 f...
    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 a...
    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 ...
    Group
  • IPV6_AUTOCONF

    Toggle global IPv6 auto-configuration (only, if global forwarding is disabled)
    Value
  • 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
  • Limit Network-Transmitted Configuration if Using Static IPv6 Addresses

    To limit the configuration information requested from other systems and accepted from the network on a system that uses statically-configured IPv6 ...
    Group
  • 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
  • net.ipv4.conf.all.accept_redirects

    Disable ICMP Redirect Acceptance
    Value
  • net.ipv4.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 redirec...
    Value
  • net.ipv4.conf.default.arp_filter

    Controls whether the ARP filter is enabled or not. 1 - Allows you to have multiple network interfaces on the same subnet, and have the ARPs for ea...
    Value
  • net.ipv4.conf.default.arp_ignore

    Control the response modes for ARP queries that resolve local target IP addresses: 0 - (default): reply for any local target IP address, configure...
    Value
  • net.ipv4.conf.all.forwarding

    Toggle IPv4 Forwarding
    Value
  • net.ipv4.conf.all.log_martians

    Disable so you don't Log Spoofed Packets, Source Routed Packets, Redirect Packets
    Value
  • net.ipv4.conf.all.rp_filter

    Enable to enforce sanity checking, also called ingress filtering or egress filtering. The point is to drop a packet if the source and destination I...
    Value
  • net.ipv4.conf.all.secure_redirects

    Enable to prevent hijacking of routing path by only allowing redirects from gateways known in routing table. Disable to refuse acceptance of secure...
    Value
  • net.ipv4.conf.all.shared_media

    Controls whether the system can send (router) or accept (host) RFC1620 shared media redirects. <code>shared_media</code> for the interface will be ...
    Value
  • net.ipv4.conf.default.accept_redirects

    Disable ICMP Redirect Acceptance?
    Value

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