Australian Cyber Security Centre (ACSC) ISM Official
Rules and Groups employed by this XCCDF Profile
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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 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 -
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 -
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 -
Enable SSH Server firewalld Firewall Exception
If the SSH server is in use, inbound connections to SSH's port should be allowed to permit remote access through SSH. In more restrictive firewalld...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 GSSAPI Authentication
Unless needed, SSH should not permit extraneous or unnecessary authentication mechanisms like GSSAPI. <br> The default SSH configuration disallows ...Rule Medium Severity -
Disable Kerberos Authentication
Unless needed, SSH should not permit extraneous or unnecessary authentication mechanisms like Kerberos. <br> The default SSH configuration disallow...Rule Medium 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 Support for User Known Hosts
SSH can allow system users to connect to systems if a cache of the remote systems public keys is available. This should be disabled. <br> ...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 Use of Strict Mode Checking
SSHs <code>StrictModes</code> option checks file and ownership permissions in the user's home directory <code>.ssh</code> folder before accepting l...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 -
Enable SSH Print Last Log
Ensure that SSH will display the date and time of the last successful account logon. <br> The default SSH configuration enables print of the date a...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 -
Distribute the SSH Server configuration to multiple files in a config directory.
Make sure to have the <code>Include /etc/ssh/sshd_config.d/*.conf</code> line in the <code>/etc/ssh/sshd_config</code> file. Ideally, don't have an...Rule Medium Severity -
System Security Services Daemon
The System Security Services Daemon (SSSD) is a system daemon that provides access to different identity and authentication providers such as Red H...Group -
Enable Smartcards in SSSD
SSSD should be configured to authenticate access to the system using smart cards. To enable smart cards in SSSD, set <code>pam_cert_auth</code> to ...Rule Medium Severity -
USBGuard daemon
The USBGuard daemon enforces the USB device authorization policy for all USB devices.Group -
Install usbguard Package
Theusbguardpackage can be installed with the following command:$ sudo yum install usbguard
Rule Medium Severity -
Enable the USBGuard Service
The USBGuard service should be enabled. The <code>usbguard</code> service can be enabled with the following command: <pre>$ sudo systemctl enable ...Rule Medium Severity -
Enable ExecShield via sysctl
By default on Oracle Linux 9 64-bit systems, ExecShield is enabled and can only be disabled if the hardware does not support ExecShield or is disab...Rule Medium Severity -
Prevent non-Privileged Users from Modifying Network Interfaces using nmcli
By default, non-privileged users are given permissions to modify networking interfaces and configurations using the <code>nmcli</code> command. Non...Rule Medium Severity -
Enable the auditadm_exec_content SELinux Boolean
By default, the SELinux boolean <code>auditadm_exec_content</code> is enabled. If this setting is disabled, it should be enabled. To enable the <c...Rule Medium Severity -
Disable the authlogin_nsswitch_use_ldap SELinux Boolean
By default, the SELinux boolean <code>authlogin_nsswitch_use_ldap</code> is disabled. If this setting is enabled, it should be disabled. To disabl...Rule Medium Severity -
Disable the authlogin_radius SELinux Boolean
By default, the SELinux boolean <code>authlogin_radius</code> is disabled. If this setting is enabled, it should be disabled. To disable the <code...Rule Medium Severity -
Enable the kerberos_enabled SELinux Boolean
By default, the SELinux boolean <code>kerberos_enabled</code> is enabled. If this setting is disabled, it should be enabled to allow confined appli...Rule Medium Severity -
Chrony Configure Pool and Server
<code>Chrony</code> is a daemon which implements the Network Time Protocol (NTP). It is designed to synchronize system clocks across a variety of s...Rule Medium Severity -
Specify Additional Remote NTP Servers
Depending on specific functional requirements of a concrete production environment, the Oracle Linux 9 system can be configured to utilize the serv...Rule Medium Severity -
Disable snmpd Service
Thesnmpdservice can be disabled with the following command:$ sudo systemctl mask --now snmpd.service
Rule Low Severity -
Configure SNMP Service to Use Only SNMPv3 or Newer
Edit <code>/etc/snmp/snmpd.conf</code>, removing any references to <code>rocommunity</code>, <code>rwcommunity</code>, or <code>com2sec</code>. Upo...Rule Medium Severity
Node 2
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