CIS Ubuntu 20.04 Level 2 Server Benchmark
Rules and Groups employed by this XCCDF Profile
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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 s...Group -
System and Software Integrity
System and software integrity can be gained by installing antivirus, increasing system encryption strength with FIPS, verifying installed software,...Group -
Package "prelink" Must not be Installed
Theprelinkpackage can be removed with the following command:$ apt-get remove prelink
Rule Medium Severity -
Software Integrity Checking
Both the AIDE (Advanced Intrusion Detection Environment) software and the RPM package management system provide mechanisms for verifying the integr...Group -
Verify Integrity with AIDE
AIDE conducts integrity checks by comparing information about files with previously-gathered information. Ideally, the AIDE database is created imm...Group -
Install AIDE
Theaidepackage can be installed with the following command:$ apt-get install aide
Rule Medium Severity -
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...Rule Medium Severity -
Configure Periodic Execution of AIDE
At a minimum, AIDE should be configured to run a weekly scan. To implement a daily execution of AIDE at 4:05am using cron, add the following line t...Rule Medium Severity -
Disk Partitioning
To ensure separation and protection of data, there are top-level system directories which should be placed on their own physical partition or logic...Group -
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...Rule Low Severity -
Ensure /tmp Located On Separate Partition
The <code>/tmp</code> directory is a world-writable directory used for temporary file storage. Ensure it has its own partition or logical volume at...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 i...Rule Low Severity -
Ensure /var/log Located On Separate Partition
System logs are stored in the <code>/var/log</code> directory. Ensure that <code>/var/log</code> has its own partition or logical volume at instal...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 volum...Rule Low Severity -
Ensure /var/tmp Located On Separate Partition
The <code>/var/tmp</code> directory is a world-writable directory used for temporary file storage. Ensure it has its own partition or logical volum...Rule Medium Severity -
GNOME Desktop Environment
GNOME is a graphical desktop environment bundled with many Linux distributions that allow users to easily interact with the operating system graphi...Group -
Remove the GDM Package Group
By removing the <code>gdm3</code> package, the system no longer has GNOME installed installed. If X Windows is not installed then the system cann...Rule Medium Severity -
Sudo
<code>Sudo</code>, which stands for "su 'do'", provides the ability to delegate authority to certain users, groups of users, or system administrato...Group -
Install sudo Package
Thesudopackage can be installed with the following command:$ apt-get install sudo
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 ma...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 CI...Rule Low Severity -
Account and Access Control
In traditional Unix security, if an attacker gains shell access to a certain login account, they can perform any action or access any file to which...Group -
Warning Banners for System Accesses
Each system should expose as little information about itself as possible. <br><br> System banners, which are typically displayed just before a logi...Group -
Modify the System Login Banner
To configure the system login banner edit <code>/etc/issue</code>. Replace the default text with a message compliant with the local site policy or...Rule Medium Severity -
Modify the System Login Banner for Remote Connections
To configure the system login banner edit <code>/etc/issue.net</code>. Replace the default text with a message compliant with the local site policy...Rule Medium Severity -
Modify the System Message of the Day Banner
To configure the system message banner edit <code>/etc/motd</code>. Replace the default text with a message compliant with the local site policy or...Rule Medium Severity -
Verify Group Ownership of System Login Banner
To properly set the group owner of/etc/issue, run the command:$ sudo chgrp root /etc/issue
Rule Medium Severity -
Verify Group Ownership of System Login Banner for Remote Connections
To properly set the group owner of/etc/issue.net, run the command:$ sudo chgrp root /etc/issue.net
Rule Medium Severity -
Verify Group Ownership of Message of the Day Banner
To properly set the group owner of/etc/motd, run the command:$ sudo chgrp root /etc/motd
Rule Medium Severity -
Verify ownership of System Login Banner
To properly set the owner of/etc/issue, run the command:$ sudo chown root /etc/issue
Rule Medium Severity -
Verify ownership of System Login Banner for Remote Connections
To properly set the owner of/etc/issue.net, run the command:$ sudo chown root /etc/issue.net
Rule Medium Severity -
Verify ownership of Message of the Day Banner
To properly set the owner of/etc/motd, run the command:$ sudo chown root /etc/motd
Rule Medium Severity -
Verify permissions on System Login Banner
To properly set the permissions of/etc/issue, run the command:$ sudo chmod 0644 /etc/issue
Rule Medium Severity -
Verify permissions on System Login Banner for Remote Connections
To properly set the permissions of/etc/issue.net, run the command:$ sudo chmod 0644 /etc/issue.net
Rule Medium Severity -
Verify permissions on Message of the Day Banner
To properly set the permissions of/etc/motd, run the command:$ sudo chmod 0644 /etc/motd
Rule Medium Severity -
Protect Accounts by Configuring PAM
PAM, or Pluggable Authentication Modules, is a system which implements modular authentication for Linux programs. PAM provides a flexible and confi...Group -
Install pam_pwquality Package
Thelibpam-pwqualitypackage can be installed with the following command:$ apt-get install libpam-pwquality
Rule Medium Severity -
Set Lockouts for Failed Password Attempts
The <code>pam_faillock</code> PAM module provides the capability to lock out user accounts after a number of failed login attempts. Its documentati...Group -
Limit Password Reuse
Do not allow users to reuse recent passwords. This can be accomplished by using the <code>remember</code> option for the <code>pam_pwhistory</code>...Rule Medium Severity -
Set Deny For Failed Password Attempts
The Ubuntu 20.04 operating system must lock an account after - at most - <xccdf-1.2:sub xmlns:xccdf-1.2="http://checklists.nist.gov/xccdf/1.2" idre...Rule Medium Severity -
Set Password Quality Requirements
The default <code>pam_pwquality</code> PAM module provides strength checking for passwords. It performs a number of checks, such as making sure pas...Group -
Set Password Quality Requirements with pam_pwquality
The <code>pam_pwquality</code> PAM module can be configured to meet requirements for a variety of policies. <br><br> For example, to configure <cod...Group -
Ensure PAM Enforces Password Requirements - Minimum Digit Characters
The pam_pwquality module's <code>dcredit</code> parameter controls requirements for usage of digits in a password. When set to a negative number, a...Rule Medium Severity -
Ensure PAM Enforces Password Requirements - Minimum Lowercase Characters
The pam_pwquality module's <code>lcredit</code> parameter controls requirements for usage of lowercase letters in a password. When set to a negativ...Rule Medium Severity -
Ensure PAM Enforces Password Requirements - Minimum Different Categories
The pam_pwquality module's <code>minclass</code> parameter controls requirements for usage of different character classes, or types, of character t...Rule Medium Severity -
Ensure PAM Enforces Password Requirements - Minimum Length
The pam_pwquality module's <code>minlen</code> parameter controls requirements for minimum characters required in a password. Add <code>minlen=<xcc...Rule Medium Severity -
Ensure PAM Enforces Password Requirements - Minimum Special Characters
The pam_pwquality module's <code>ocredit=</code> parameter controls requirements for usage of special (or "other") characters in a password. When s...Rule Medium Severity -
Ensure PAM Enforces Password Requirements - Authentication Retry Prompts Permitted Per-Session
To configure the number of retry prompts that are permitted per-session: Edit the <code>pam_pwquality.so</code> statement in <code>/etc/pam.d/com...Rule Medium Severity -
Ensure PAM Enforces Password Requirements - Minimum Uppercase Characters
The pam_pwquality module's <code>ucredit=</code> parameter controls requirements for usage of uppercase letters in a password. When set to a negati...Rule Medium Severity
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