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Guide to the Secure Configuration of Alibaba Cloud Linux 2

Rules, Groups, and Values defined within the XCCDF Benchmark

  • Disable DHCP Client

    DHCP is the default network configuration method provided by the system installer, and common on many networks. Nevertheless, manual management of ...
    Group
  • Disable DHCP Server

    The DHCP server <code>dhcpd</code> is not installed or activated by default. If the software was installed and activated, but the system does not n...
    Group
  • DNS Server

    Most organizations have an operational need to run at least one nameserver. However, there are many common attacks involving DNS server software, a...
    Group
  • Secure Apache Configuration

    The <code>httpd</code> configuration file is <code>/etc/httpd/conf/httpd.conf</code>. Apply the recommendations in the remainder of this section to...
    Group
  • HTTPD Log Level

    The setting for LogLevel in /etc/httpd/conf/httpd.conf
    Value
  • 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
  • Disable DNS Server

    DNS software should be disabled on any systems which does not need to be a nameserver. Note that the BIND DNS server software is not installed on A...
    Group
  • Uninstall bind Package

    The <code>named</code> service is provided by the <code>bind</code> package. The <code>bind</code> package can be removed with the following comman...
    Rule Low Severity
  • Isolate DNS from Other Services

    This section discusses mechanisms for preventing the DNS server from interfering with other services. This is done both to protect the remainder of...
    Group
  • Run DNS Software in a chroot Jail

    Install the <code>bind-chroot</code> package: <pre>$ sudo yum install bind-chroot</pre> Place a valid named.conf file inside the chroot jail: <pre>...
    Group
  • Run DNS Software on Dedicated Servers

    Since DNS is a high-risk service which must frequently be made available to the entire Internet, it is strongly recommended that no other services ...
    Group
  • Protect DNS Data from Tampering or Attack

    This section discusses DNS configuration options which make it more difficult for attackers to gain access to private DNS data or to modify DNS data.
    Group
  • Use Views to Partition External and Internal Information

    If it is not possible to run external and internal nameservers on separate physical systems, run BIND9 and simulate this feature using views. Edit ...
    Group
  • Run Separate DNS Servers for External and Internal Queries

    Is it possible to run external and internal nameservers on separate systems? If so, follow the configuration guidance in this section. On the exter...
    Group
  • Docker Service

    The docker service is necessary to create containers, which are self-sufficient and self-contained applications using the resource isolation fe...
    Group
  • Application Whitelisting Daemon

    Fapolicyd (File Access Policy Daemon) implements application whitelisting to decide file access rights. Applications that are known via a reputatio...
    Group
  • fapolicyd Must be Configured to Limit Access to Users Home Folders

    fapolicyd needs be configured so that users cannot give access to their home folders to other users.
    Rule Medium Severity
  • FTP Server

    FTP is a common method for allowing remote access to files. Like telnet, the FTP protocol is unencrypted, which means that passwords and other data...
    Group
  • Disable vsftpd if Possible

    To minimize attack surface, disable vsftpd if at all possible.
    Group
  • Configure vsftpd to Provide FTP Service if Necessary

    The primary vsftpd configuration file is /etc/vsftpd.conf, if that file exists, or /etc/vsftpd/vsftpd.conf if it does not.
    Group
  • Configure Firewalls to Protect the FTP Server

    By default, <code>iptables</code> blocks access to the ports used by the web server. To configure <code>iptables</code> to allow port 21 traffic,...
    Rule Unknown Severity
  • Restrict the Set of Users Allowed to Access FTP

    This section describes how to disable non-anonymous (password-based) FTP logins, or, if it is not possible to do this entirely due to legacy applic...
    Group
  • Limit Users Allowed FTP Access if Necessary

    If there is a mission-critical reason for users to access their accounts via the insecure FTP protocol, limit the set of users who are allowed this...
    Rule Unknown Severity
  • Use vsftpd to Provide FTP Service if Necessary

    If your use-case requires FTP service, install and set-up vsftpd to provide it.
    Group
  • Web Server

    The web server is responsible for providing access to content via the HTTP protocol. Web servers represent a significant security risk because: <br...
    Group
  • Disable Apache if Possible

    If Apache was installed and activated, but the system does not need to act as a web server, then it should be disabled and removed from the system.
    Group
  • Disable NGINX if Possible

    If NGINX was installed and activated, but the system does not need to act as a web server, then it should be removed from the system.
    Group
  • Install Apache if Necessary

    If <code>httpd</code> was not installed and activated, but the system needs to act as a web server, then it should be installed on the system. Foll...
    Group
  • Confirm Minimal Built-in Modules Installed

    The default <code>httpd</code> installation minimizes the number of modules that are compiled directly into the binary (<code>core prefork http_cor...
    Group
  • Configure Operating System to Protect Web Server

    The following configuration steps should be taken on the system which hosts the web server, in order to provide as safe an environment as possible ...
    Group
  • Run httpd in a chroot Jail if Practical

    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
  • Restrict File and Directory Access

    Minimize access to critical httpd files and directories.
    Group
  • Configure PERL Securely

    PERL (Practical Extraction and Report Language) is an interpreted language optimized for scanning arbitrary text files, extracting information from...
    Group
  • Configure PHP Securely

    PHP is a widely-used and often misconfigured server-side scripting language. It should be used with caution, but configured appropriately when need...
    Group
  • Directory Restrictions

    The Directory tags in the web server configuration file allow finer grained access control for a specified directory. All web directories should be...
    Group
  • Minimize Web Server Loadable Modules

    A default installation of <code>httpd</code> includes a plethora of dynamically shared objects (DSO) that are loaded at run-time. Unlike the aforem...
    Group
  • httpd Core Modules

    These modules comprise a basic subset of modules that are likely needed for base <code>httpd</code> functionality; ensure they are not commented ou...
    Group
  • Minimize Modules for HTTP Basic Authentication

    The following modules are necessary if this web server will provide content that will be restricted by a password. <br><br> Authentication can be p...
    Group
  • Minimize Configuration Files Included

    The <code>Include</code> directive directs <code>httpd</code> to load supplementary configuration files from a provided path. The default configura...
    Group
  • 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

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