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Guide to the Secure Configuration of Fedora

Rules, Groups, and Values defined within the XCCDF Benchmark

  • Minimize Various Optional Components

    The following modules perform very specific tasks, sometimes providing access to just a few additional directives. If such functionality is not req...
    Group
  • Use Appropriate Modules to Improve httpd's Security

    Among the modules available for <code>httpd</code> are several whose use may improve the security of the web server installation. This section reco...
    Group
  • Deploy mod_security

    The <code>security</code> module provides an application level firewall for <code>httpd</code>. Following its installation with the base ruleset, s...
    Group
  • Deploy mod_ssl

    Because HTTP is a plain text protocol, all traffic is susceptible to passive monitoring. If there is a need for confidentiality, SSL should be conf...
    Group
  • Restrict Web Server Information Leakage

    The <code>ServerTokens</code> and <code>ServerSignature</code> directives determine how much information the web server discloses about the configu...
    Group
  • Configure HTTPD-Served Web Content Securely

    Running <code>httpd</code> inside a <code>chroot</code> jail is designed to isolate the web server process to a small section of the filesystem, li...
    Group
  • Web Login Banner Verbiage

    Enter an appropriate login banner for your organization. Please note that new lines must be expressed by the '\n' character and special characters ...
    Value
  • Use Denial-of-Service Protection Modules

    Denial-of-service attacks are difficult to detect and prevent while maintaining acceptable access to authorized users. However, some traffic-shapin...
    Group
  • IMAP and POP3 Server

    Dovecot provides IMAP and POP3 services. It is not installed by default. The project page at <a href="http://www.dovecot.org">http://www.dovec...
    Group
  • Configure Dovecot if Necessary

    If the system will operate as an IMAP or POP3 server, the dovecot software should be configured securely by following the recommendations below.
    Group
  • Allow IMAP Clients to Access the Server

    The default iptables configuration does not allow inbound access to any services. This modification will allow remote hosts to initiate connection...
    Group
  • Uninstall cyrus-imapd Package

    The cyrus-imapd package can be removed with the following command:
    $ sudo dnf erase cyrus-imapd
    Rule Unknown Severity
  • Configure OpenLDAP Clients

    This section provides information on which security settings are important to configure in OpenLDAP clients by manually editing the appropriate con...
    Group
  • Ensure LDAP client is not installed

    The Lightweight Directory Access Protocol (LDAP) is a service that provides a method for looking up information from a central database. The <code>...
    Rule Low Severity
  • Configure OpenLDAP Server

    This section details some security-relevant settings for an OpenLDAP server.
    Group
  • Install and Protect LDAP Certificate Files

    Create the PKI directory for LDAP certificates if it does not already exist: <pre>$ sudo mkdir /etc/pki/tls/ldap $ sudo chown root:root /etc/pki/tl...
    Group
  • Mail Server Software

    Mail servers are used to send and receive email over the network. Mail is a very common service, and Mail Transfer Agents (MTAs) are obvious target...
    Group
  • The Postfix package is installed

    A mail server is required for sending emails. The <code>postfix</code> package can be installed with the following command: <pre> $ sudo dnf instal...
    Rule Medium Severity
  • Uninstall Sendmail Package

    Sendmail is not the default mail transfer agent and is not installed by default. The <code>sendmail</code> package can be removed with the followin...
    Rule Medium Severity
  • Configure SMTP For Mail Clients

    This section discusses settings for Postfix in a submission-only e-mail configuration.
    Group
  • Postfix Network Interfaces

    The setting for inet_interfaces in /etc/postfix/main.cf
    Value
  • Postfix relayhost

    Specify the host all outbound email should be routed into.
    Value
  • Postfix Root Mail Alias

    Specify an email address (string) for a root mail alias.
    Value
  • Configure System to Forward All Mail For The Root Account

    Make sure that mails delivered to root user are forwarded to a monitored email address. Make sure that the address <xccdf-1.2:sub idref="xccdf_org....
    Rule Medium Severity
  • Configure System to Forward All Mail From Postmaster to The Root Account

    Verify the administrators are notified in the event of an audit processing failure. Check that the "/etc/aliases" file has a defined value for "roo...
    Rule Medium Severity
  • Configure System to Forward All Mail through a specific host

    Set up a relay host that will act as a gateway for all outbound email. Edit the file <code>/etc/postfix/main.cf</code> to ensure that only the foll...
    Rule Medium Severity
  • Configure Operating System to Protect Mail Server

    The guidance in this section is appropriate for any host which is operating as a site MTA, whether the mail server runs using Sendmail, Postfix, or...
    Group
  • Configure SSL Certificates for Use with SMTP AUTH

    If SMTP AUTH is to be used, the use of SSL to protect credentials in transit is strongly recommended. There are also configurations for which it ma...
    Group
  • Ensure Security of Postfix SSL Certificate

    Create the PKI directory for mail certificates, if it does not already exist: <pre>$ sudo mkdir /etc/pki/tls/mail $ sudo chown root:root /etc/pki/t...
    Group
  • Configure Postfix if Necessary

    Postfix stores its configuration files in the directory /etc/postfix by default. The primary configuration file is /etc/postfix/main.cf.
    Group
  • Configure Postfix Resource Usage to Limit Denial of Service Attacks

    Edit <code>/etc/postfix/main.cf</code>. Edit the following lines to configure the amount of system resources Postfix can consume: <pre>default_proc...
    Group
  • Control Mail Relaying

    Postfix's mail relay controls are implemented with the help of the smtpd recipient restrictions option, which controls the restrictions placed on t...
    Group
  • Enact SMTP Recipient Restrictions

    To configure Postfix to restrict addresses to which it will send mail, see: <a href="http://www.postfix.org/SMTPD_ACCESS_README.html#danger">h...
    Group
  • Enact SMTP Relay Restrictions

    To configure Postfix to restrict addresses to which it will send mail, see: <a href="http://www.postfix.org/SMTPD_ACCESS_README.html#danger">h...
    Group
  • Verify Ownership on SSH Server Public *.pub Key Files

    SSH server public keys, files that match the /etc/ssh/*.pub glob, must be owned by root user.
    Rule Medium Severity
  • Use TLS for SMTP AUTH

    Postfix provides options to use TLS for certificate-based authentication and encrypted sessions. An encrypted session protects the information that...
    Group
  • Configure Trusted Networks and Hosts

    Edit <code>/etc/postfix/main.cf</code>, and configure the contents of the <code>mynetworks</code> variable in one of the following ways: <ul> <li>I...
    Group
  • Require SMTP AUTH Before Relaying from Untrusted Clients

    SMTP authentication allows remote clients to relay mail safely by requiring them to authenticate before submitting mail. Postfix's SMTP AUTH uses a...
    Group
  • NFS and RPC

    The Network File System is a popular distributed filesystem for the Unix environment, and is very widely deployed. This section discusses the circ...
    Group
  • Uninstall nfs-utils Package

    The nfs-utils package can be removed with the following command:
    $ sudo dnf erase nfs-utils
    Rule Low Severity
  • Disable All NFS Services if Possible

    If there is not a reason for the system to operate as either an NFS client or an NFS server, follow all instructions in this section to disable sub...
    Group
  • Disable netfs if Possible

    To determine if any network filesystems handled by netfs are currently mounted on the system execute the following command: <pre>$ mount -t nfs,nfs...
    Group
  • Disable Network File Systems (netfs)

    The netfs script manages the boot-time mounting of several types of networked filesystems, of which NFS and Samba are the most common. If these fil...
    Rule Unknown Severity
  • Disable Services Used Only by NFS

    If NFS is not needed, disable the NFS client daemons nfslock, rpcgssd, and rpcidmapd. <br><br> All of these daemons run with elevated privileges, a...
    Group
  • Disable Network File System Lock Service (nfslock)

    The Network File System Lock (nfslock) service starts the required remote procedure call (RPC) processes which allow clients to lock files on the s...
    Rule Unknown Severity
  • Disable rpcbind Service

    The rpcbind utility maps RPC services to the ports on which they listen. RPC processes notify rpcbind when they start, registering the ports they a...
    Rule Low Severity
  • Disable Secure RPC Client Service (rpcgssd)

    The rpcgssd service manages RPCSEC GSS contexts required to secure protocols that use RPC (most often Kerberos and NFS). The rpcgssd service is the...
    Rule Unknown Severity
  • Authorize USB hubs in USBGuard daemon

    To allow authorization of USB hub devices by USBGuard daemon, add line <code>allow with-interface match-all { 09:00:* }</code> to <code>/etc/usbgua...
    Rule Medium Severity
  • Disable RPC ID Mapping Service (rpcidmapd)

    The rpcidmapd service is used to map user names and groups to UID and GID numbers on NFSv4 mounts. If NFS is not in use on the local system then th...
    Rule Unknown Severity
  • Configure All Systems which Use NFS

    The steps in this section are appropriate for all systems which run NFS, whether they operate as clients or as servers.
    Group

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