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Guide to the Secure Configuration of Ubuntu 20.04

Rules, Groups, and Values defined within the XCCDF Benchmark

  • System Settings

    Contains rules that check correct system settings.
    Group
  • Installing and Maintaining Software

    The following sections contain information on security-relevant choices during the initial operating system installation process and the setup of software updates.
    Group
  • Prefer to use a 64-bit Operating System when supported

    Prefer installation of 64-bit operating systems when the CPU supports it.
    Rule Medium Severity
  • System and Software Integrity

    System and software integrity can be gained by installing antivirus, increasing system encryption strength with FIPS, verifying installed software, enabling SELinux, installing an Intrusion Prevent...
    Group
  • Software Integrity Checking

    Both the AIDE (Advanced Intrusion Detection Environment) software and the RPM package management system provide mechanisms for verifying the integrity of installed software. AIDE uses snapshots of ...
    Group
  • Verify Integrity with AIDE

    AIDE conducts integrity checks by comparing information about files with previously-gathered information. Ideally, the AIDE database is created immediately after initial system configuration, and t...
    Group
  • Install AIDE

    The aide package can be installed with the following command:
    $ apt-get install aide
    Rule Medium Severity
  • net.ipv6.conf.all.accept_ra

    Accept all router advertisements?
    Value
  • net.ipv6.conf.all.accept_redirects

    Toggle ICMP Redirect Acceptance
    Value
  • net.ipv6.conf.default.accept_ra

    Accept default router advertisements by default?
    Value
  • net.ipv6.conf.default.accept_redirects

    Toggle ICMP Redirect Acceptance By Default
    Value
  • net.ipv4.conf.default.rp_filter

    Enables source route verification
    Value
  • Build and Test AIDE Database

    Run the following command to generate a new database: <pre>$ sudo aideinit</pre> By default, the database will be written to the file <code>/var/lib/aide/aide.db.new</code>. Storing the databas...
    Rule Medium Severity
  • Configure AIDE to Verify the Audit Tools

    The operating system file integrity tool must be configured to protect the integrity of the audit tools.
    Rule Medium Severity
  • Federal Information Processing Standard (FIPS)

    The Federal Information Processing Standard (FIPS) is a computer security standard which is developed by the U.S. Government and industry working groups to validate the quality of cryptographic mod...
    Group
  • Verify '/proc/sys/crypto/fips_enabled' exists

    On a system where FIPS 140-2 mode is enabled, <code>/proc/sys/crypto/fips_enabled</code> must exist. To verify FIPS mode, run the following command: <pre>cat /proc/sys/crypto/fips_enabled</pre> ...
    Rule High Severity
  • System Cryptographic Policies

    Linux has the capability to centrally configure cryptographic polices. The command <code>update-crypto-policies</code> is used to set the policy applicable for the various cryptographic back-ends, ...
    Group
  • Harden SSH client Crypto Policy

    Crypto Policies are means of enforcing certain cryptographic settings for selected applications including OpenSSH client. To override the system wide crypto policy for Openssh client, place a file ...
    Rule Medium Severity
  • Operating System Vendor Support and Certification

    The assurance of a vendor to provide operating system support and maintenance for their product is an important criterion to ensure product stability and security over the life of the product. A ce...
    Group
  • The Installed Operating System Is FIPS 140-2 Certified

    To enable processing of sensitive information the operating system must provide certified cryptographic modules compliant with FIPS 140-2 standard. Ubuntu Linux is supported by Canonical Ltd. As t...
    Rule High Severity
  • Configure Backups of User Data

    The operating system must conduct backups of user data contained in the operating system. The operating system provides utilities for automating backups of user data. Commercial and open-source pro...
    Rule Medium Severity
  • McAfee Endpoint Security Software

    In DoD environments, McAfee Host-based Security System (HBSS) and VirusScan Enterprise for Linux (VSEL) is required to be installed on all systems.
    Group
  • McAfee Endpoint Security for Linux (ENSL)

    McAfee Endpoint Security for Linux (ENSL) is a suite of software applications used to monitor, detect, and defend computer networks and systems.
    Group
  • Install McAfee Endpoint Security for Linux (ENSL)

    Install McAfee Endpoint Security for Linux antivirus software which is provided for DoD systems and uses signatures to search for the presence of viruses on the filesystem. The <code>mfetp</code> ...
    Rule Medium Severity
  • McAfee Host-Based Intrusion Detection Software (HBSS)

    McAfee Host-based Security System (HBSS) is a suite of software applications used to monitor, detect, and defend computer networks and systems.
    Group
  • Install the Host Intrusion Prevention System (HIPS) Module

    Install the McAfee Host Intrusion Prevention System (HIPS) Module if it is absolutely necessary. If SELinux is enabled, do not install or enable this module.
    Rule Medium Severity
  • Ensure /home Located On Separate Partition

    If user home directories will be stored locally, create a separate partition for <code>/home</code> at installation time (or migrate it later using LVM). If <code>/home</code> will be mounted from ...
    Rule Low Severity
  • Ensure /srv Located On Separate Partition

    If a file server (FTP, TFTP...) is hosted locally, create a separate partition for <code>/srv</code> at installation time (or migrate it later using LVM). If <code>/srv</code> will be mounted from ...
    Rule Unknown Severity
  • Ensure /tmp Located On Separate Partition

    The /tmp directory is a world-writable directory used for temporary file storage. Ensure it has its own partition or logical volume at installation time, or migrate it using LVM.
    Rule Low Severity
  • Ensure /var Located On Separate Partition

    The <code>/var</code> directory is used by daemons and other system services to store frequently-changing data. Ensure that <code>/var</code> has its own partition or logical volume at installation...
    Rule Low Severity
  • Ensure /var/log Located On Separate Partition

    System logs are stored in the /var/log directory. Ensure that /var/log has its own partition or logical volume at installation time, or migrate it using LVM.
    Rule Low Severity
  • Ensure /var/log/audit Located On Separate Partition

    Audit logs are stored in the <code>/var/log/audit</code> directory. Ensure that <code>/var/log/audit</code> has its own partition or logical volume at installation time, or migrate it using LVM. M...
    Rule Low Severity
  • Ensure /var/tmp Located On Separate Partition

    The /var/tmp directory is a world-writable directory used for temporary file storage. Ensure it has its own partition or logical volume at installation time, or migrate it using LVM.
    Rule Medium Severity
  • Ensure Sudo Logfile Exists - sudo logfile

    A custom log sudo file can be configured with the 'logfile' tag. This rule configures a sudo custom logfile at the default location suggested by CIS, which uses /var/log/sudo.log.
    Rule Low Severity
  • Configure GNOME3 DConf User Profile

    By default, DConf provides a standard user profile. This profile contains a list of DConf configuration databases. The user profile and database always take the highest priority. As such the DConf ...
    Rule High Severity
  • Configure GNOME Login Screen

    In the default GNOME desktop, the login is displayed after system boot and can display user accounts, allow users to reboot the system, and allow users to login automatically and/or with a guest ac...
    Group
  • Disable the GNOME3 Login User List

    In the default graphical environment, users logging directly into the system are greeted with a login screen that displays all known users. This functionality should be disabled by setting <code>di...
    Rule Medium Severity
  • Disable XDMCP in GDM

    XDMCP is an unencrypted protocol, and therefore, presents a security risk, see e.g. <a href="https://help.gnome.org/admin/gdm/stable/security.html.en_GB#xdmcpsecurity">XDMCP Gnome docs</a>. To dis...
    Rule High Severity
  • Configure GNOME Screen Locking

    In the default GNOME3 desktop, the screen can be locked by selecting the user name in the far right corner of the main panel and selecting <b>Lock</b>. <br> <br> The following sections deta...
    Group
  • Enable GNOME3 Screensaver Lock After Idle Period

    To activate locking of the screensaver in the GNOME3 desktop when it is activated, add or set <code>lock-enabled</code> to <code>true</code> in <code>/etc/dconf/db/local.d/00-security-settings</co...
    Rule Medium Severity
  • GNOME System Settings

    GNOME provides configuration and functionality to a graphical desktop environment that changes grahical configurations or allow a user to perform actions that users normally would not be able to do...
    Group
  • Sudo

    <code>Sudo</code>, which stands for "su 'do'", provides the ability to delegate authority to certain users, groups of users, or system administrators. When configured for system users and/or groups...
    Group
  • Sudo - logfile value

    Specify the sudo logfile to use. The default value used here matches the example location from CIS, which uses /var/log/sudo.log.
    Value
  • Install sudo Package

    The sudo package can be installed with the following command:
    $ apt-get install sudo
    Rule Medium Severity
  • Ensure Privileged Escalated Commands Cannot Execute Other Commands - sudo NOEXEC

    The sudo <code>NOEXEC</code> tag, when specified, prevents user executed commands from executing other commands, like a shell for example. This should be enabled by making sure that the <code>NOEXE...
    Rule High Severity
  • Ensure Only Users Logged In To Real tty Can Execute Sudo - sudo requiretty

    The sudo <code>requiretty</code> tag, when specified, will only execute sudo commands from users logged in to a real tty. This should be enabled by making sure that the <code>requiretty</code> tag ...
    Rule Medium Severity
  • Ensure Only Users Logged In To Real tty Can Execute Sudo - sudo use_pty

    The sudo <code>use_pty</code> tag, when specified, will only execute sudo commands from users logged in to a real tty. This should be enabled by making sure that the <code>use_pty</code> tag exists...
    Rule Medium Severity
  • Ensure Users Re-Authenticate for Privilege Escalation - sudo NOPASSWD

    The sudo <code>NOPASSWD</code> tag, when specified, allows a user to execute commands using sudo without having to authenticate. This should be disabled by making sure that the <code>NOPASSWD</code...
    Rule Medium Severity
  • Ensure Users Re-Authenticate for Privilege Escalation - sudo

    The sudo <code>NOPASSWD</code> and <code>!authenticate</code> option, when specified, allows a user to execute commands using sudo without having to authenticate. This should be disabled by making ...
    Rule Medium Severity
  • Only the VDSM User Can Use sudo NOPASSWD

    The sudo <code>NOPASSWD</code> tag, when specified, allows a user to execute commands using sudo without having to authenticate. Only the <code>vdsm</code> user should have this capability in any s...
    Rule Medium Severity

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