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Guide to the Secure Configuration of SUSE Linux Enterprise 12

Rules, Groups, and Values defined within the XCCDF Benchmark

  • 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 zypper install logr...
    Rule Medium Severity
  • Ensure Logrotate Runs Periodically

    The <code>logrotate</code> utility allows for the automatic rotation of log files. The frequency of rotation is specified in <code>/etc/logrotate....
    Rule Medium Severity
  • Enable logrotate Timer

    The logrotate timer can be enabled with the following command:
    $ sudo systemctl enable logrotate.timer
    Rule Medium Severity
  • Configure rsyslogd to Accept Remote Messages If Acting as a Log Server

    By default, <code>rsyslog</code> does not listen over the network for log messages. If needed, modules can be enabled to allow the rsyslog daemon t...
    Group
  • Ensure syslog-ng is Installed

    syslog-ng can be installed in replacement of rsyslog. The <code>syslog-ng-core</code> package can be installed with the following command: <pre> $ ...
    Rule Medium Severity
  • Enable syslog-ng Service

    The <code>syslog-ng</code> service (in replacement of rsyslog) provides syslog-style logging by default on Debian. The <code>syslog-ng</code> serv...
    Rule Medium Severity
  • Verify Group Who Owns Backup passwd File

    To properly set the group owner of /etc/passwd-, run the command:
    $ sudo chgrp root /etc/passwd-
    Rule Medium Severity
  • Enable rsyslog to Accept Messages via TCP, if Acting As Log Server

    The <code>rsyslog</code> daemon should not accept remote messages unless the system acts as a log server. If the system needs to act as a central l...
    Rule Unknown Severity
  • Enable rsyslog to Accept Messages via UDP, if Acting As Log Server

    The <code>rsyslog</code> daemon should not accept remote messages unless the system acts as a log server. If the system needs to act as a central l...
    Rule Unknown Severity
  • Ensure rsyslog Does Not Accept Remote Messages Unless Acting As Log Server

    The <code>rsyslog</code> daemon should not accept remote messages unless the system acts as a log server. To ensure that it is not listening on the...
    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
  • Configure TLS for rsyslog remote logging

    Configure <code>rsyslog</code> to use Transport Layer Security (TLS) support for logging to remote server for the Forwarding Output Module in <code...
    Rule Medium Severity
  • Configure CA certificate for rsyslog remote logging

    Configure CA certificate for <code>rsyslog</code> logging to remote server using Transport Layer Security (TLS) using correct path for the <code>De...
    Rule Medium Severity
  • 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
  • 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
  • Ensure System is Not Acting as a Network Sniffer

    The system should not be acting as a network sniffer, which can capture all traffic on the network to which it is connected. Run the following to d...
    Rule Medium Severity
  • 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 zypper 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
  • Strengthen the Default Ruleset

    The default rules can be strengthened. The system scripts that activate the firewall rules expect them to be defined in configuration files under t...
    Group
  • IPSec Support

    Support for Internet Protocol Security (IPsec) is provided with Libreswan.
    Group
  • Install libreswan Package

    The libreswan package provides an implementation of IPsec and IKE, which permits the creation of secure tunnels over untrusted networks. The <code>...
    Rule Medium Severity
  • Install strongswan Package

    The Strongswan package provides an implementation of IPsec and IKE, which permits the creation of secure tunnels over untrusted networks. The <code...
    Rule Medium Severity
  • net.ipv4.conf.default.rp_filter

    Enables source route verification
    Value
  • 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 zypper 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
  • 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
  • net.ipv4.conf.default.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
  • 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
  • Ensure Outbound and Established Connections are Configured

    Configure the firewall rules for new outbound and established connections.
    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
  • 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 ...
    Rule Low Severity
  • 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
  • conman_can_network SELinux Boolean

    default - Default SELinux boolean setting.
    on - SELinux boolean is enabled.
    off - SELinux boolean is disabled.
    Value

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