Guide to the Secure Configuration of Red Hat Enterprise Linux 8
Rules, Groups, and Values defined within the XCCDF Benchmark
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Disable Kerberos Authentication
Unless needed, SSH should not permit extraneous or unnecessary authentication mechanisms like Kerberos. <br> The default SSH configuration disallows authentication validation through Kerberos. The ...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 line in <code>/etc/ssh/sshd_config</code>: <pre>Pe...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 capability to encrypt remote X11 connections when SSH...Rule Medium Severity -
Enable Public Key Authentication
Enable SSH login with public keys. <br> The default SSH configuration enables authentication based on public keys. The appropriate configuration is used if no value is set for <code>PubkeyAuthentic...Rule Medium Severity -
Enable Encrypted X11 Forwarding
By default, remote X11 connections are not encrypted when initiated by users. SSH has the capability to encrypt remote X11 connections when SSH's <code>X11Forwarding</code> option is enabled. <br> ...Rule High 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 and time of the last login. The appropriate configu...Rule Medium Severity -
Force frequent session key renegotiation
The <code>RekeyLimit</code> parameter specifies how often the session key of the is renegotiated, both in terms of amount of data that may be transmitted and the time elapsed.<br> To decrease the d...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. The appropriate configuration is used if no value ...Rule Low Severity -
Set SSH Daemon LogLevel to VERBOSE
The <code>VERBOSE</code> parameter configures the SSH daemon to record login and logout activity. To specify the log level in SSH, add or correct the following line in <code>/etc/ssh/sshd_config<...Rule Medium 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 failures reaches half this value, additional failures ar...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 <code>/etc/ssh/sshd_config</code> as follows: <pre>Ma...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 dropped until authentication succeeds or the Login...Rule Medium Severity -
Use Only FIPS 140-2 Validated Key Exchange Algorithms
Limit the key exchange algorithms to those which are FIPS-approved. Add or modify the following line in <code>/etc/crypto-policies/back-ends/opensshserver.config</code> <pre>CRYPTO_POLICY=...Rule Medium Severity -
Enable Use of Privilege Separation
When enabled, SSH will create an unprivileged child process that has the privilege of the authenticated user. To enable privilege separation in SSH, add or correct the following line in the <code>/...Rule Medium Severity -
SSH server uses strong entropy to seed
To set up SSH server to use entropy from a high-quality source, edit the <code>/etc/sysconfig/sshd</code> file. The <code>SSH_USE_STRONG_RNG</code> configuration value determines how many bytes of ...Rule Low Severity -
Prevent remote hosts from connecting to the proxy display
The SSH daemon should prevent remote hosts from connecting to the proxy display. <br> The default SSH configuration for <code>X11UseLocalhost</code> is <code>yes</code>, which prevents remote hosts...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 Hat's IdM, Microsoft's AD, openLDAP, MIT Kerberos, ...Group -
Install sssd-ipa Package
Thesssd-ipapackage can be installed with the following command:$ sudo yum install sssd-ipa
Rule Medium Severity -
Enable the SSSD Service
The SSSD service should be enabled. Thesssdservice can be enabled with the following command:$ sudo systemctl enable sssd.service
Rule Medium Severity -
Certificate status checking in SSSD
Multifactor solutions that require devices separate from information systems gaining access include, for example, hardware tokens providing time-based or challenge-response authenticators and smart...Rule Medium Severity -
Enable Certmap in SSSD
SSSD should be configured to verify the certificate of the user or group. To set this up ensure that section like <code>certmap/testing.test/rule_name</code> is setup in <code>/etc/sssd/sssd.conf<...Rule Medium Severity -
Configure PAM in SSSD Services
SSSD should be configured to run SSSD <code>pam</code> services. To configure SSSD to known SSH hosts, add <code>pam</code> to <code>services</code> under the <code>[sssd]</code> section in <code>/...Rule Medium Severity -
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 <code>True</code> under the <code>[pam]</code> sec...Rule Medium Severity -
Configure SSSD's Memory Cache to Expire
SSSD's memory cache should be configured to set to expire records after <code><xccdf-1.2:sub idref="xccdf_org.ssgproject.content_value_var_sssd_memcache_timeout" use="legacy"></xccdf-1.2:sub></code...Rule Medium Severity -
System Audit Directories Must Be Group Owned By Root
All audit directories must be group owned by root user. By default, the path for audit log is <pre>/var/log/audit/</pre>. To properly set the group owner of <code>/var/log/audit</code>, run the co...Rule Medium Severity -
Configure SSSD to Expire Offline Credentials
SSSD should be configured to expire offline credentials after 1 day. Check if SSSD allows cached authentications with the following command: <pre> $ sudo grep cache_credentials /etc/sssd/sssd.conf...Rule Medium Severity -
Configure SSSD to Expire SSH Known Hosts
SSSD should be configured to expire keys from known SSH hosts after <code><xccdf-1.2:sub idref="xccdf_org.ssgproject.content_value_var_sssd_ssh_known_hosts_timeout" use="legacy"></xccdf-1.2:sub></c...Rule Medium Severity -
System Security Services Daemon (SSSD) - LDAP
The System Security Services Daemon (SSSD) is a system daemon that provides access to different identity and authentication providers such as Red Hat's IdM, Microsoft's AD, openLDAP, MIT Kerberos, ...Group -
Configure SSSD LDAP Backend Client CA Certificate
Configure SSSD to implement cryptography to protect the integrity of LDAP remote access sessions. By setting the <pre>ldap_tls_cacert</pre> option in <pre>/etc/sssd/sssd.conf</pre> to point to the ...Rule Medium Severity -
Configure SSSD LDAP Backend Client CA Certificate Location
Configure SSSD to implement cryptography to protect the integrity of LDAP remote access sessions. By setting the <pre>ldap_tls_cacertdir</pre> option in <pre>/etc/sssd/sssd.conf</pre> to point to t...Rule Medium Severity -
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 boot into graphical user mode. This prevents the s...Rule Medium Severity -
Disable X Windows Startup By Setting Default Target
Systems that do not require a graphical user interface should only boot by default into <code>multi-user.target</code> mode. This prevents accidental booting of the system into a <code>graphical.ta...Rule Medium Severity -
Ensure the default plugins for the audit dispatcher are Installed
The audit-audispd-plugins package should be installed.Rule Medium Severity -
Ensure the audit Subsystem is Installed
The audit package should be installed.Rule Medium Severity -
Extend Audit Backlog Limit for the Audit Daemon
To improve the kernel capacity to queue all log events, even those which occurred prior to the audit daemon, add the argument <code>audit_backlog_limit=8192</code> to the default GRUB 2 command lin...Rule Low Severity -
Configure auditd Data Retention
The audit system writes data to <code>/var/log/audit/audit.log</code>. By default, <code>auditd</code> rotates 5 logs by size (6MB), retaining a maximum of 30MB of data in total, and refuses to wri...Group -
Audit failure mode
This variable is the setting for the -f option in Audit configuration which sets the failure mode of audit. This option lets you determine how you want the kernel to handle critical errors. Possibl...Value -
Set type of computer node name logging in audit logs
To configure Audit daemon to use a unique identifier as computer node name in the audit events, set <code>name_format</code> to <code><xccdf-1.2:sub idref="xccdf_org.ssgproject.content_value_var_au...Rule Medium Severity -
Record Events that Modify User/Group Information via open_by_handle_at syscall - /etc/group
The audit system should collect write events to /etc/group file for all group and root. If the <code>auditd</code> daemon is configured to use the <code>augenrules</code> program to read audit rule...Rule Medium Severity -
Record Events that Modify User/Group Information via openat syscall - /etc/group
The audit system should collect write events to /etc/group file for all users and root. If the <code>auditd</code> daemon is configured to use the <code>augenrules</code> program to read audit rule...Rule Medium Severity -
Record Events that Modify User/Group Information via open syscall - /etc/gshadow
The audit system should collect write events to /etc/gshadow file for all users and root. If the <code>auditd</code> daemon is configured to use the <code>augenrules</code> program to read audit ru...Rule Medium Severity -
Record Events that Modify User/Group Information via open_by_handle_at syscall - /etc/gshadow
The audit system should collect write events to /etc/gshadow file for all users and root. If the <code>auditd</code> daemon is configured to use the <code>augenrules</code> program to read audit ru...Rule Medium Severity -
Record Events that Modify User/Group Information via open syscall - /etc/passwd
The audit system should collect write events to /etc/passwd file for all users and root. If the <code>auditd</code> daemon is configured to use the <code>augenrules</code> program to read audit rul...Rule Medium Severity -
Record Events that Modify User/Group Information via openat syscall - /etc/passwd
The audit system should collect write events to /etc/passwd file for all users and root. If the <code>auditd</code> daemon is configured to use the <code>augenrules</code> program to read audit rul...Rule Medium Severity -
Record Events that Modify User/Group Information via open syscall - /etc/shadow
The audit system should collect write events to /etc/shadow file for all users and root. If the <code>auditd</code> daemon is configured to use the <code>augenrules</code> program to read audit rul...Rule Medium Severity -
Record Events that Modify User/Group Information via openat syscall - /etc/shadow
The audit system should collect write events to /etc/shadow file for all users and root. If the <code>auditd</code> daemon is configured to use the <code>augenrules</code> program to read audit rul...Rule Medium Severity -
Make the auditd Configuration Immutable
If the <code>auditd</code> daemon is configured to use the <code>augenrules</code> program to read audit rules during daemon startup (the default), add the following line to a file with suffix <cod...Rule Medium Severity -
Configure immutable Audit login UIDs
Configure kernel to prevent modification of login UIDs once they are set. Changing login UIDs while this configuration is enforced requires special capabilities which are not available to unprivile...Rule Medium Severity -
Record Events that Modify the System's Mandatory Access Controls
If the <code>auditd</code> daemon is configured to use the <code>augenrules</code> program to read audit rules during daemon startup (the default), add the following line to a file with suffix <cod...Rule Medium Severity -
Record Events that Modify the System's Mandatory Access Controls in usr/share
If the <code>auditd</code> daemon is configured to use the <code>augenrules</code> program to read audit rules during daemon startup (the default), add the following line to a file with suffix <cod...Rule Medium Severity
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