Guide to the Secure Configuration of Red Hat Enterprise Linux 9
Rules, Groups, and Values defined within the XCCDF Benchmark
-
Verify Permissions on cron.weekly
To properly set the permissions of/etc/cron.weekly
, run the command:$ sudo chmod 0700 /etc/cron.weekly
Rule Medium Severity -
Verify Permissions on crontab
To properly set the permissions of/etc/crontab
, run the command:$ sudo chmod 0600 /etc/crontab
Rule Medium Severity -
Restrict at and cron to Authorized Users if Necessary
The <code>/etc/cron.allow</code> and <code>/etc/at.allow</code> files contain lists of users who are allowed to use <code>cron</code> and at to del...Group -
Ensure that /etc/at.deny does not exist
The file/etc/at.deny
should not exist. Use/etc/at.allow
instead.Rule Medium Severity -
Ensure that /etc/cron.deny does not exist
The file/etc/cron.deny
should not exist. Use/etc/cron.allow
instead.Rule Medium Severity -
Verify Group Who Owns /etc/at.allow file
If <code>/etc/at.allow</code> exists, it must be group-owned by <code>root</code>. To properly set the group owner of <code>/etc/at.allow</code>, ...Rule Medium Severity -
Verify Group Who Owns /etc/cron.allow file
If <code>/etc/cron.allow</code> exists, it must be group-owned by <code>root</code>. To properly set the group owner of <code>/etc/cron.allow</cod...Rule Medium Severity -
Verify User Who Owns /etc/cron.allow file
If <code>/etc/cron.allow</code> exists, it must be owned by <code>root</code>. To properly set the owner of <code>/etc/cron.allow</code>, run the ...Rule Medium Severity -
Verify Permissions on /etc/at.allow file
If <code>/etc/at.allow</code> exists, it must have permissions <code>0600</code> or more restrictive. To properly set the permissions of <code>/e...Rule Medium Severity -
Verify Permissions on /etc/cron.allow file
If <code>/etc/cron.allow</code> exists, it must have permissions <code>0600</code> or more restrictive. To properly set the permissions of <code>...Rule Medium Severity -
Deprecated services
Some deprecated software services impact the overall system security due to their behavior (leak of confidentiality in network exchange, usage as u...Group -
Uninstall the inet-based telnet server
The inet-based telnet daemon should be uninstalled.Rule High Severity -
Uninstall the nis package
The support for Yellowpages should not be installed unless it is required.Rule Low Severity -
Uninstall the ntpdate package
ntpdate is a historical ntp synchronization client for unixes. It sould be uninstalled.Rule Low Severity -
Uninstall the ssl compliant telnet server
Thetelnet
daemon, even with ssl support, should be uninstalled.Rule High Severity -
Uninstall the telnet server
The telnet daemon should be uninstalled.Rule High Severity -
DHCP
The Dynamic Host Configuration Protocol (DHCP) allows systems to request and obtain an IP address and other configuration parameters from a server....Group -
Configure DHCP Client if Necessary
If DHCP must be used, then certain configuration changes can minimize the amount of information it receives and applies from the network, and thus ...Group -
Minimize the DHCP-Configured Options
Create the file <code>/etc/dhcp/dhclient.conf</code>, and add an appropriate setting for each of the ten configuration settings which can be obtain...Rule Unknown Severity -
Configure DHCP Server
If the system must act as a DHCP server, the configuration information it serves should be minimized. Also, support for other protocols and DNS-upd...Group -
Minimize Served Information
Edit /etc/dhcp/dhcpd.conf. Examine each address range section within the file, and ensure that the following options are not defined unless there i...Rule Unknown Severity -
Disable DHCP Client
DHCP is the default network configuration method provided by the system installer, and common on many networks. Nevertheless, manual management of ...Group -
Disable DHCP Server
The DHCP server <code>dhcpd</code> is not installed or activated by default. If the software was installed and activated, but the system does not n...Group -
Uninstall DHCP Server Package
If the system does not need to act as a DHCP server, the dhcp package can be uninstalled. The <code>dhcp-server</code> package can be removed with...Rule Medium Severity -
Disable DHCP Service
The <code>dhcpd</code> service should be disabled on any system that does not need to act as a DHCP server. The <code>dhcpd</code> service can be ...Rule Medium Severity -
DNS Server
Most organizations have an operational need to run at least one nameserver. However, there are many common attacks involving DNS server software, a...Group -
Uninstall dnsmasq Package
dnsmasq is a lightweight tool that provides DNS caching, DNS forwarding and DHCP (Dynamic Host Configuration Protocol) services. <br> The <code>dns...Rule Low Severity -
Disable DNS Server
DNS software should be disabled on any systems which does not need to be a nameserver. Note that the BIND DNS server software is not installed on R...Group -
Uninstall bind Package
The <code>named</code> service is provided by the <code>bind</code> package. The <code>bind</code> package can be removed with the following comman...Rule Low Severity -
Disable named Service
Thenamed
service can be disabled with the following command:$ sudo systemctl mask --now named.service
Rule Medium Severity -
Isolate DNS from Other Services
This section discusses mechanisms for preventing the DNS server from interfering with other services. This is done both to protect the remainder of...Group -
Run DNS Software in a chroot Jail
Install the <code>bind-chroot</code> package: <pre>$ sudo yum install bind-chroot</pre> Place a valid named.conf file inside the chroot jail: <pre>...Group -
Run DNS Software on Dedicated Servers
Since DNS is a high-risk service which must frequently be made available to the entire Internet, it is strongly recommended that no other services ...Group -
Protect DNS Data from Tampering or Attack
This section discusses DNS configuration options which make it more difficult for attackers to gain access to private DNS data or to modify DNS data.Group -
Use Views to Partition External and Internal Information
If it is not possible to run external and internal nameservers on separate physical systems, run BIND9 and simulate this feature using views. Edit ...Group -
Run Separate DNS Servers for External and Internal Queries
Is it possible to run external and internal nameservers on separate systems? If so, follow the configuration guidance in this section. On the exter...Group -
Docker Service
The docker service is necessary to create containers, which are self-sufficient and self-contained applications using the resource isolation fe...Group -
Application Whitelisting Daemon
Fapolicyd (File Access Policy Daemon) implements application whitelisting to decide file access rights. Applications that are known via a reputatio...Group -
Install fapolicyd Package
Thefapolicyd
package can be installed with the following command:$ sudo dnf install fapolicyd
Rule Medium Severity -
Enable the File Access Policy Service
The File Access Policy service should be enabled. The <code>fapolicyd</code> service can be enabled with the following command: <pre>$ sudo system...Rule Medium Severity -
Configure Fapolicy Module to Employ a Deny-all, Permit-by-exception Policy to Allow the Execution of Authorized Software Programs.
The Fapolicy module must be configured to employ a deny-all, permit-by-exception policy to allow the execution of authorized software programs and ...Rule Medium Severity -
fapolicyd Must be Configured to Limit Access to Users Home Folders
fapolicyd needs be configured so that users cannot give access to their home folders to other users.Rule Medium Severity -
FTP Server
FTP is a common method for allowing remote access to files. Like telnet, the FTP protocol is unencrypted, which means that passwords and other data...Group -
Remove ftp Package
FTP (File Transfer Protocol) is a traditional and widely used standard tool for transferring files between a server and clients over a network, esp...Rule Low Severity -
Disable vsftpd if Possible
To minimize attack surface, disable vsftpd if at all possible.Group -
Uninstall vsftpd Package
Thevsftpd
package can be removed with the following command:$ sudo dnf erase vsftpd
Rule High Severity -
Disable vsftpd Service
Thevsftpd
service can be disabled with the following command:$ sudo systemctl mask --now vsftpd.service
Rule Medium Severity -
Configure vsftpd to Provide FTP Service if Necessary
The primary vsftpd configuration file is/etc/vsftpd.conf
, if that file exists, or/etc/vsftpd/vsftpd.conf
if it does not.Group -
Configure Firewalls to Protect the FTP Server
By default, <code>iptables</code> blocks access to the ports used by the web server. To configure <code>iptables</code> to allow port 21 traffic,...Rule Unknown Severity -
Restrict the Set of Users Allowed to Access FTP
This section describes how to disable non-anonymous (password-based) FTP logins, or, if it is not possible to do this entirely due to legacy applic...Group
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.