CIS Ubuntu 22.04 Level 2 Server Benchmark
Rules and Groups employed by this XCCDF Profile
-
Rlogin, Rsh, and Rexec
The Berkeley r-commands are legacy services which allow cleartext remote access and have an insecure trust model.Group -
Uninstall rsh Package
Thersh-clientpackage contains the client commands for the rsh servicesRule Unknown Severity -
Remove Rsh Trust Files
The files <code>/etc/hosts.equiv</code> and <code>~/.rhosts</code> (in each user's home directory) list remote hosts and users that are trusted by ...Rule High Severity -
Chat/Messaging Services
The talk software makes it possible for users to send and receive messages across systems through a terminal session.Group -
Uninstall talk Package
The <code>talk</code> package contains the client program for the Internet talk protocol, which allows the user to chat with other users on differe...Rule Medium Severity -
Telnet
The telnet protocol does not provide confidentiality or integrity for information transmitted on the network. This includes authentication informat...Group -
Remove telnet Clients
The telnet client allows users to start connections to other systems via the telnet protocol.Rule Low Severity -
Print Support
The Common Unix Printing System (CUPS) service provides both local and network printing support. A system running the CUPS service can accept print...Group -
Uninstall CUPS Package
Thecupspackage can be removed with the following command:$ apt-get remove cups
Rule Unknown Severity -
Disable the CUPS Service
Thecupsservice can be disabled with the following command:$ sudo systemctl mask --now cups.service
Rule Unknown Severity -
Proxy Server
A proxy server is a very desirable target for a potential adversary because much (or all) sensitive data for a given infrastructure may flow throug...Group -
Disable Squid if Possible
If Squid was installed and activated, but the system does not need to act as a proxy server, then it should be disabled and removed.Group -
Uninstall squid Package
Thesquidpackage can be removed with the following command:$ apt-get remove squid
Rule Unknown Severity -
Samba(SMB) Microsoft Windows File Sharing Server
When properly configured, the Samba service allows Linux systems to provide file and print sharing to Microsoft Windows systems. There are two soft...Group -
Disable Samba if Possible
Even after the Samba server package has been installed, it will remain disabled. Do not enable this service unless it is absolutely necessary to pr...Group -
Uninstall Samba Package
Thesambapackage can be removed with the following command:$ apt-get remove samba
Rule Unknown Severity -
SNMP Server
The Simple Network Management Protocol allows administrators to monitor the state of network devices, including computers. Older versions of SNMP w...Group -
Disable SNMP Server if Possible
The system includes an SNMP daemon that allows for its remote monitoring, though it not installed by default. If it was installed and activated but...Group -
Uninstall net-snmp Package
The <code>snmp</code> package provides the snmpd service. The <code>snmp</code> package can be removed with the following command: <pre> $ apt-get...Rule Unknown Severity -
SSH Server
The SSH protocol is recommended for remote login and remote file transfer. SSH provides confidentiality and integrity for data exchanged between tw...Group -
Verify Group Who Owns SSH Server config file
To properly set the group owner of/etc/ssh/sshd_config, run the command:$ sudo chgrp root /etc/ssh/sshd_config
Rule Medium Severity -
Verify Owner on SSH Server config file
To properly set the owner of/etc/ssh/sshd_config, run the command:$ sudo chown root /etc/ssh/sshd_config
Rule Medium Severity -
Verify Permissions on SSH Server config file
To properly set the permissions of/etc/ssh/sshd_config, run the command:$ sudo chmod 0600 /etc/ssh/sshd_config
Rule Medium Severity -
Verify Permissions on SSH Server Private *_key Key Files
SSH server private keys - files that match the <code>/etc/ssh/*_key</code> glob, have to have restricted permissions. If those files are owned by t...Rule Medium Severity -
Verify Permissions on SSH Server Public *.pub Key Files
To properly set the permissions of/etc/ssh/*.pub, run the command:$ sudo chmod 0644 /etc/ssh/*.pub
Rule Medium Severity -
Configure OpenSSH Server if Necessary
If the system needs to act as an SSH server, then certain changes should be made to the OpenSSH daemon configuration file <code>/etc/ssh/sshd_confi...Group -
Set SSH Client Alive Count Max
The SSH server sends at most <code>ClientAliveCountMax</code> messages during a SSH session and waits for a response from the SSH client. The optio...Rule Medium Severity -
Set SSH Client Alive Interval
SSH allows administrators to set a network responsiveness timeout interval. After this interval has passed, the unresponsive client will be automat...Rule Medium Severity -
Disable Host-Based Authentication
SSH's cryptographic host-based authentication is more secure than <code>.rhosts</code> authentication. However, it is not recommended that hosts un...Rule Medium Severity -
Disable SSH Access via Empty Passwords
Disallow SSH login with empty passwords. The default SSH configuration disables logins with empty passwords. The appropriate configuration is used ...Rule High Severity -
Disable SSH Support for .rhosts Files
SSH can emulate the behavior of the obsolete rsh command in allowing users to enable insecure access to their accounts via <code>.rhosts</code> fil...Rule Medium Severity -
Disable SSH Root Login
The root user should never be allowed to login to a system directly over a network. To disable root login via SSH, add or correct the following lin...Rule Medium Severity -
Disable SSH TCP Forwarding
The <code>AllowTcpForwarding</code> parameter specifies whether TCP forwarding is permitted. To disable TCP forwarding, add or correct the followin...Rule Medium Severity -
Disable X11 Forwarding
The X11Forwarding parameter provides the ability to tunnel X11 traffic through the connection to enable remote graphic connections. SSH has the cap...Rule Medium Severity -
Do Not Allow SSH Environment Options
Ensure that users are not able to override environment variables of the SSH daemon. <br> The default SSH configuration disables environment process...Rule Medium Severity -
Enable PAM
UsePAM Enables the Pluggable Authentication Module interface. If set to “yes” this will enable PAM authentication using ChallengeResponseAuthentica...Rule Medium Severity -
Enable SSH Warning Banner
To enable the warning banner and ensure it is consistent across the system, add or correct the following line in <code>/etc/ssh/sshd_config</code>...Rule Medium Severity -
Limit Users' SSH Access
By default, the SSH configuration allows any user with an account to access the system. There are several options available to limit which users an...Rule Unknown Severity -
Ensure SSH LoginGraceTime is configured
The <code>LoginGraceTime</code> parameter to the SSH server specifies the time allowed for successful authentication to the SSH server. The longer ...Rule Medium Severity -
Set LogLevel to INFO
The INFO parameter specifices that record login and logout activity will be logged. <br> The default SSH configuration sets the log level to INFO. ...Rule Low Severity -
Set SSH authentication attempt limit
The <code>MaxAuthTries</code> parameter specifies the maximum number of authentication attempts permitted per connection. Once the number of failur...Rule Medium Severity -
Set SSH MaxSessions limit
The <code>MaxSessions</code> parameter specifies the maximum number of open sessions permitted from a given connection. To set MaxSessions edit <co...Rule Medium Severity -
Ensure SSH MaxStartups is configured
The MaxStartups parameter specifies the maximum number of concurrent unauthenticated connections to the SSH daemon. Additional connections will be ...Rule Medium Severity -
Use Only Strong Ciphers
Limit the ciphers to strong algorithms. Counter (CTR) mode is also preferred over cipher-block chaining (CBC) mode. The following line in <code>/et...Rule Medium Severity -
Use Only Strong Key Exchange algorithms
Limit the Key Exchange to strong algorithms. The following line in <code>/etc/ssh/sshd_config</code> demonstrates use of those: <pre>KexAlgorithms ...Rule Medium Severity -
Use Only Strong MACs
Limit the MACs to strong hash algorithms. The following line in <code>/etc/ssh/sshd_config</code> demonstrates use of those MACs: <pre>MACs <xccdf-...Rule Medium Severity -
X Window System
The X Window System implementation included with the system is called X.org.Group -
Disable X Windows
Unless there is a mission-critical reason for the system to run a graphical user interface, ensure X is not set to start automatically at boot and ...Group -
Remove the X Windows Package Group
By removing the xorg-x11-server-common package, the system no longer has X Windows installed. If X Windows is not installed then the system cannot ...Rule Medium Severity -
Verify No .forward Files Exist
The.forwardfile specifies an email address to forward the user's mail to.Rule Medium Severity
Node 2
The content of the drawer really is up to you. It could have form fields, definition lists, text lists, labels, charts, progress bars, etc. Spacing recommendation is 24px margins. You can put tabs in here, and can also make the drawer scrollable.
Capacity
Modules