Guide to the Secure Configuration of Red Hat Enterprise Linux 7
Rules, Groups, and Values defined within the XCCDF Benchmark
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Configure ntpd To Run As ntp User
ntp is a daemon which implements the Network Time Protocol (NTP). It is designed to synchronize system clocks across a variety of systems and use a...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 -
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 -
Uninstall rsync Package
The rsyncd service can be used to synchronize files between systems over network links. The <code>rsync</code> package can be removed with the foll...Rule Medium Severity -
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 -
Install tcp_wrappers Package
When network services are using the <code>xinetd</code> service, the <code>tcp_wrappers</code> package should be installed. The <code>tcp_wrappers<...Rule Medium Severity -
Uninstall xinetd Package
Thexinetd
package can be removed with the following command:$ sudo yum erase xinetd
Rule Low 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 -
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 -
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 -
Telnet
The telnet protocol does not provide confidentiality or integrity for information transmitted on the network. This includes authentication informat...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 -
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-server Package
Thetalk-server
package can be removed with the following command:$ sudo yum erase talk-server
Rule Medium 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 -
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 -
Disable Printer Browsing Entirely if Possible
By default, CUPS listens on the network for printer list broadcasts on UDP port 631. This functionality is called printer browsing. To disable prin...Rule Unknown Severity -
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 -
Disable tftp Service
The <code>tftp</code> service should be disabled. The <code>tftp</code> service can be disabled with the following command: <pre>$ sudo systemctl ...Rule High 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 -
Uninstall CUPS Package
Thecups
package can be removed with the following command:$ sudo yum erase cups
Rule Unknown Severity -
Disable the CUPS Service
Thecups
service can be disabled with the following command:$ sudo systemctl mask --now cups.service
Rule Unknown Severity -
Install the Samba Common Package
The <code>samba-common</code> package should be installed. The <code>samba-common</code> package can be installed with the following command: <pre>...Rule Medium Severity -
Disable Print Server Capabilities
To prevent remote users from potentially connecting to and using locally configured printers, disable the CUPS print server sharing capabilities. T...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
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