Guide to the Secure Configuration of Oracle Linux 7
Rules, Groups, and Values defined within the XCCDF Benchmark
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Enable the NTP Daemon
Thentpd
service can be enabled with the following command:$ sudo systemctl enable ntpd.service
Rule Medium Severity -
SSH Max Keep Alive Count
Specify the maximum number of idle message counts before session is terminated.Value -
Remove NIS Client
The Network Information Service (NIS), formerly known as Yellow Pages, is a client-server directory service protocol used to distribute system conf...Rule Unknown Severity -
Configure Time Service Maxpoll Interval
The <code>maxpoll</code> should be configured to <xccdf-1.2:sub idref="xccdf_org.ssgproject.content_value_var_time_service_set_maxpoll" use="legacy...Rule Medium Severity -
Specify Additional Remote NTP Servers
Depending on specific functional requirements of a concrete production environment, the Oracle Linux 7 system can be configured to utilize the serv...Rule Medium Severity -
Specify a Remote NTP Server
Depending on specific functional requirements of a concrete production environment, the Oracle Linux 7 system can be configured to utilize the serv...Rule Medium Severity -
Ensure Chrony is only configured with the server directive
Check that Chrony only has time sources configured with theserver
directive.Rule Medium Severity -
A remote time server for Chrony is configured
<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
Additional NTP servers can be specified for time synchronization in the file <code>/etc/ntp.conf</code>. To do so, add additional lines of the fol...Rule Unknown Severity -
Specify a Remote NTP Server
To specify a remote NTP server for time synchronization, edit the file <code>/etc/ntp.conf</code>. Add or correct the following lines, substituting...Rule Medium Severity -
Chat/Messaging Services
The talk software makes it possible for users to send and receive messages across systems through a terminal session.Group -
Obsolete Services
This section discusses a number of network-visible services which have historically caused problems for system security, and for which disabling or...Group -
Ensure rsyncd service is disabled
Thersyncd
service can be disabled with the following command:$ sudo systemctl mask --now rsyncd.service
Rule Medium Severity -
Xinetd
The <code>xinetd</code> service acts as a dedicated listener for some network services (mostly, obsolete ones) and can be used to provide access co...Group -
Uninstall xinetd Package
Thexinetd
package can be removed with the following command:$ sudo yum erase xinetd
Rule Low Severity -
Disable xinetd Service
Thexinetd
service can be disabled with the following command:$ sudo systemctl mask --now xinetd.service
Rule Medium Severity -
Ensure /etc/hosts.deny is configured
The file <code>/etc/hosts.deny</code> together with <code>/etc/hosts.allow</code> provides a simple access control mechanism for network services s...Rule Medium Severity -
Verify Group Ownership of /etc/hosts.allow
To properly set the group owner of/etc/hosts.allow
, run the command:$ sudo chgrp root /etc/hosts.allow
Rule Medium Severity -
Verify Group Ownership of /etc/hosts.deny
To properly set the group owner of/etc/hosts.deny
, run the command:$ sudo chgrp root /etc/hosts.deny
Rule Medium Severity -
Verify Ownership of /etc/hosts.allow
To properly set the owner of/etc/hosts.allow
, run the command:$ sudo chown root /etc/hosts.allow
Rule Medium Severity -
Verify Ownership of /etc/hosts.deny
To properly set the owner of/etc/hosts.deny
, run the command:$ sudo chown root /etc/hosts.deny
Rule Medium Severity -
Verify Permissions on /etc/hosts.allow
To properly set the permissions of/etc/hosts.allow
, run the command:$ sudo chmod 0644 /etc/hosts.allow
Rule Medium Severity -
Verify Permissions on /etc/hosts.deny
To properly set the permissions of/etc/hosts.deny
, run the command:$ sudo chmod 0644 /etc/hosts.deny
Rule Medium Severity -
NIS
The Network Information Service (NIS), also known as 'Yellow Pages' (YP), and its successor NIS+ have been made obsolete by Kerberos, LDAP, and oth...Group -
Uninstall talk-server Package
Thetalk-server
package can be removed with the following command:$ sudo yum erase talk-server
Rule Medium Severity -
Uninstall ypserv Package
Theypserv
package can be removed with the following command:$ sudo yum erase ypserv
Rule High Severity -
Disable ypbind Service
The <code>ypbind</code> service, which allows the system to act as a client in a NIS or NIS+ domain, should be disabled. The <code>ypbind</code> s...Rule Medium Severity -
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-server Package
Thersh-server
package can be removed with the following command:$ sudo yum erase rsh-server
Rule High Severity -
Uninstall rsh Package
Thersh
package contains the client commands for the rsh servicesRule Unknown Severity -
Disable rexec Service
The <code>rexec</code> service, which is available with the <code>rsh-server</code> package and runs as a service through xinetd or separately as a...Rule High Severity -
Disable rlogin Service
The <code>rlogin</code> service, which is available with the <code>rsh-server</code> package and runs as a service through xinetd or separately as ...Rule High Severity -
Disable rsh Service
The <code>rsh</code> service, which is available with the <code>rsh-server</code> package and runs as a service through xinetd or separately as a s...Rule High Severity -
Remove Host-Based Authentication Files
The <code>shosts.equiv</code> file lists remote hosts and users that are trusted by the local system. To remove these files, run the following comm...Rule High 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 -
Remove User Host-Based Authentication Files
The <code>~/.shosts</code> (in each user's home directory) files list remote hosts and users that are trusted by the local system. To remove these ...Rule High Severity -
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 -
Uninstall telnet-server Package
Thetelnet-server
package can be removed with the following command:$ sudo yum erase telnet-server
Rule High Severity -
Remove telnet Clients
The telnet client allows users to start connections to other systems via the telnet protocol.Rule Low Severity -
Disable telnet Service
Make sure that the activation of the <code>telnet</code> service on system boot is disabled. The <code>telnet</code> socket can be disabled with t...Rule High Severity -
TFTP Server
TFTP is a lightweight version of the FTP protocol which has traditionally been used to configure networking equipment. However, TFTP provides littl...Group -
TFTP server secure directory
Specify the directory which is used by TFTP server as a root directory when running in secure mode.Value -
Uninstall tftp-server Package
Thetftp-server
package can be removed with the following command:$ sudo yum erase tftp-server
Rule High Severity -
Remove tftp Daemon
Trivial File Transfer Protocol (TFTP) is a simple file transfer protocol, typically used to automatically transfer configuration or boot files betw...Rule Low Severity -
Ensure tftp Daemon Uses Secure Mode
If running the Trivial File Transfer Protocol (TFTP) service is necessary, it should be configured to change its root directory at startup. To do s...Rule Medium 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 -
Configure the CUPS Service if Necessary
CUPS provides the ability to easily share local printers with other systems over the network. It does this by allowing systems to share lists of av...Group -
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
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