PCI-DSS v4.0 Control Baseline for Alibaba Cloud Linux 2
Rules and Groups employed by this XCCDF Profile
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Verify Owner on cron.daily
To properly set the owner of/etc/cron.daily
, run the command:$ sudo chown root /etc/cron.daily
Rule Medium Severity -
Verify Owner on cron.hourly
To properly set the owner of/etc/cron.hourly
, run the command:$ sudo chown root /etc/cron.hourly
Rule Medium Severity -
Verify Owner on cron.monthly
To properly set the owner of/etc/cron.monthly
, run the command:$ sudo chown root /etc/cron.monthly
Rule Medium Severity -
Verify Owner on cron.weekly
To properly set the owner of/etc/cron.weekly
, run the command:$ sudo chown root /etc/cron.weekly
Rule Medium Severity -
Verify Owner on crontab
To properly set the owner of/etc/crontab
, run the command:$ sudo chown root /etc/crontab
Rule Medium Severity -
Verify Permissions on cron.d
To properly set the permissions of/etc/cron.d
, run the command:$ sudo chmod 0700 /etc/cron.d
Rule Medium Severity -
Verify Permissions on cron.daily
To properly set the permissions of/etc/cron.daily
, run the command:$ sudo chmod 0700 /etc/cron.daily
Rule Medium Severity -
Verify Permissions on cron.hourly
To properly set the permissions of/etc/cron.hourly
, run the command:$ sudo chmod 0700 /etc/cron.hourly
Rule Medium Severity -
Verify Permissions on cron.monthly
To properly set the permissions of/etc/cron.monthly
, run the command:$ sudo chmod 0700 /etc/cron.monthly
Rule Medium Severity -
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 delay execution of processes. If these files exist an...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>, run the command: <pre>$ sudo chgrp root /etc/at.al...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</code>, run the command: <pre>$ sudo chgrp root /etc/c...Rule Medium Severity -
Verify User Who Owns /etc/at.allow file
If <code>/etc/at.allow</code> exists, it must be owned by <code>root</code>. To properly set the owner of <code>/etc/at.allow</code>, run the command: <pre>$ sudo chown root /etc/at.allow </pre> ...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 command: <pre>$ sudo chown root /etc/cron.allow </...Rule Medium Severity -
Verify Permissions on /etc/at.allow file
If <code>/etc/at.allow</code> exists, it must have permissions <code>0640</code> or more restrictive. To properly set the permissions of <code>/etc/at.allow</code>, run the command: <pre>$ sudo c...Rule Medium Severity -
Verify Permissions on /etc/cron.allow file
If <code>/etc/cron.allow</code> exists, it must have permissions <code>0640</code> or more restrictive. To properly set the permissions of <code>/etc/cron.allow</code>, run the command: <pre>$ su...Rule Medium Severity -
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 targets of network attack. Ensure that systems are not r...Group -
Configure SMTP For Mail Clients
This section discusses settings for Postfix in a submission-only e-mail configuration.Group -
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 = <xccdf-1.2:sub idref="xccdf_org.ssgproject.conten...Rule Medium Severity -
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 circumstances under which it is possible to disable NF...Group -
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 subsystems required by NFS.Group -
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, and many listen for network connections. I...Group -
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 are listening on and the RPC program numbers they e...Rule Low Severity -
Network Time Protocol
The Network Time Protocol is used to manage the system clock over a network. Computer clocks are not very accurate, so time will drift unpredictably on unmanaged systems. Central time protocols can...Group -
The Chrony package is installed
System time should be synchronized between all systems in an environment. This is typically done by establishing an authoritative time server or set of servers and having all systems synchronize th...Rule Medium Severity -
Enable the NTP Daemon
Run the following command to determine the current status of the <code>chronyd</code> service: <pre>$ sudo systemctl is-active chronyd</pre> If the service is running, it should return the follo...Rule Medium Severity -
Enable the NTP Daemon
Thentpd
service can be enabled with the following command:$ sudo systemctl enable ntpd.service
Rule Medium Severity -
Ensure that chronyd is running under chrony user account
chrony 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 source that is highly accurate. More informati...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 systems and use a source that is highly accurate. M...Rule Medium 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 the IP or hostname of a remote NTP server for <em...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 severely limiting the service has been the best a...Group -
Ensure rsyncd service is disabled
Thersyncd
service can be disabled with the following command:$ sudo systemctl mask --now rsyncd.service
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 other modern centralized authentication services. NIS...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 configuration files. The NIS client (<code>ypbind</cod...Rule Unknown 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 Package
Thersh
package contains the client commands for the rsh servicesRule Unknown 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 different systems. Talk is a communication program which ...Rule Medium Severity -
Telnet
The telnet protocol does not provide confidentiality or integrity for information transmitted on the network. This includes authentication information such as passwords. Organizations which use tel...Group -
Remove telnet Clients
The telnet client allows users to start connections to other systems via the telnet protocol.Rule Low Severity -
SSH Server
The SSH protocol is recommended for remote login and remote file transfer. SSH provides confidentiality and integrity for data exchanged between two systems, as well as server authentication, throu...Group -
Verify Permissions on SSH Server config file
To properly set the permissions of/etc/ssh/sshd_config
, run the command:$ sudo chmod 0600 /etc/ssh/sshd_config
Rule Medium Severity -
Verify Permissions on SSH Server Private *_key Key Files
SSH server private keys - files that match the <code>/etc/ssh/*_key</code> glob, have to have restricted permissions. If those files are owned by the <code>root</code> user and the <code>root</code...Rule Medium Severity -
Verify Permissions on SSH Server Public *.pub Key Files
To properly set the permissions of/etc/ssh/*.pub
, run the command:$ sudo chmod 0644 /etc/ssh/*.pub
Rule Medium Severity -
Configure OpenSSH Server if Necessary
If the system needs to act as an SSH server, then certain changes should be made to the OpenSSH daemon configuration file <code>/etc/ssh/sshd_config</code>. The following recommendations can be app...Group
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