Guide to the Secure Configuration of Red Hat Enterprise Linux 8
Rules, Groups, and Values defined within the XCCDF Benchmark
-
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 -
Disable Postfix Network Listening
Edit the file <code>/etc/postfix/main.cf</code> to ensure that only the following <code>inet_interfaces</code> line appears: <pre>inet_interfaces =...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 -
Make Each System a Client or a Server, not Both
If NFS must be used, it should be deployed in the simplest configuration possible to avoid maintainability problems which may lead to unnecessary s...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 SMTP Greeting Banner
Edit <code>/etc/postfix/main.cf</code>, and add or correct the following line, substituting some other wording for the banner information if you pr...Rule Low Severity -
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 -
Prevent Unrestricted Mail Relaying
Modify the <pre>/etc/postfix/main.cf</pre> file to restrict client connections to the local network with the following command: <pre>$ sudo postcon...Rule Medium Severity -
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 -
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 -
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 -
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
Thenfs-utilspackage can be removed with the following command:$ sudo yum 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 -
Uninstall rpcbind Package
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 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 -
Configure NFS Services to Use Fixed Ports (NFSv3 and NFSv2)
Firewalling should be done at each host and at the border firewalls to protect the NFS daemons from remote access, since NFS servers should never b...Group -
Configure lockd to use static TCP port
Configure the <code>lockd</code> daemon to use a static TCP port as opposed to letting the RPC Bind service dynamically assign a port. Edit the fil...Rule Unknown Severity -
Configure lockd to use static UDP port
Configure the <code>lockd</code> daemon to use a static UDP port as opposed to letting the RPC Bind service dynamically assign a port. Edit the fil...Rule Unknown Severity -
Configure mountd to use static port
Configure the <code>mountd</code> daemon to use a static port as opposed to letting the RPC Bind service dynamically assign a port. Edit the file <...Rule Unknown Severity -
Configure statd to use static port
Configure the <code>statd</code> daemon to use a static port as opposed to letting the RPC Bind service dynamically assign a port. Edit the file <c...Rule Unknown Severity -
Configure NFS Clients
The steps in this section are appropriate for systems which operate as NFS clients.Group -
Disable NFS Server Daemons
There is no need to run the NFS server daemons <code>nfs</code> and <code>rpcsvcgssd</code> except on a small number of properly secured systems de...Group -
Disable Network File System (nfs)
The Network File System (NFS) service allows remote hosts to mount and interact with shared filesystems on the local system. If the local system is...Rule Unknown Severity -
Disable Secure RPC Server Service (rpcsvcgssd)
The rpcsvcgssd service manages RPCSEC GSS contexts required to secure protocols that use RPC (most often Kerberos and NFS). The rpcsvcgssd service ...Rule Unknown Severity -
Specify UID and GID for Anonymous NFS Connections
To specify the UID and GID for remote root users, edit the <code>/etc/exports</code> file and add the following for each export: <pre> anonuid=<cod...Rule Unknown Severity -
Uninstall Samba Package
Thesambapackage can be removed with the following command:$ sudo yum erase samba
Rule Unknown Severity -
Mount Remote Filesystems with Restrictive Options
Edit the file <code>/etc/fstab</code>. For each filesystem whose type (column 3) is <code>nfs</code> or <code>nfs4</code>, add the text <code>,node...Group -
Mount Remote Filesystems with Kerberos Security
Add the <code>sec=krb5:krb5i:krb5p</code> option to the fourth column of <code>/etc/fstab</code> for the line which controls mounting of any NFS mo...Rule Medium Severity -
Mount Remote Filesystems with nodev
Add thenodevoption to the fourth column of/etc/fstabfor the line which controls mounting of any NFS mounts.Rule Medium Severity -
Mount Remote Filesystems with noexec
Add thenoexecoption to the fourth column of/etc/fstabfor the line which controls mounting of any NFS mounts.Rule Medium Severity -
Mount Remote Filesystems with nosuid
Add thenosuidoption to the fourth column of/etc/fstabfor the line which controls mounting of any NFS mounts.Rule Medium Severity -
Configure NFS Servers
The steps in this section are appropriate for systems which operate as NFS servers.Group -
Ensure All-Squashing Disabled On All Exports
The <code>all_squash</code> maps all uids and gids to an anonymous user. This should be disabled by removing any instances of the <code>all_squash<...Rule Low Severity -
Ensure Insecure File Locking is Not Allowed
By default the NFS server requires secure file-lock requests, which require credentials from the client in order to lock a file. Most NFS clients s...Rule Medium Severity -
Restrict NFS Clients to Privileged Ports
By default, the server NFS implementation requires that all client requests be made from ports less than 1024. If your organization has control ove...Rule Unknown Severity -
Use Kerberos Security on All Exports
Using Kerberos on all exported mounts prevents a malicious client or user from impersonating a system user. To cryptography authenticate users to t...Rule Medium Severity
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.