LDAPAccountManager/lam/docs/manual-sources/appendix-security.xml

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<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
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  <appendix id="a_security">
    <title>Security</title>

    <section id="a_configPasswords">
      <title>LAM configuration passwords</title>

      <para>LAM supports a two level authorization system for its
      configuration. Therefore, there are two types of configuration
      passwords:</para>

      <itemizedlist>
        <listitem>
          <para><emphasis role="bold">master configuration
          password:</emphasis> needed to change general settings,
          create/delete server profiles and self service profiles</para>
        </listitem>

        <listitem>
          <para><emphasis role="bold">server profile password:</emphasis> used
          to change the settings of a server profile (e.g. LDAP server and
          account types to manage)</para>
        </listitem>
      </itemizedlist>

      <para>The master configuration password can be used to reset a server
      profile password. Each server profile has its own profile
      password.</para>

      <para>Both password types are stored as hash values in the configuration
      files for enhanced security.</para>
    </section>

    <section>
      <title>Use of SSL</title>

      <para>The data which is transfered between you and LAM is very
      sensitive. Please always use SSL encrypted connections between LAM and
      your browser to protect yourself against network sniffers.</para>
    </section>

    <section>
      <title>LDAP with SSL and TLS</title>

      <para>SSL will be used if you use ldaps://servername in your
      configuration profile. TLS can be activated with the "Activate TLS"
      option.</para>

      <para>If your LDAP server uses a SSL certificate of a well-know
      certificate authority (CA) then you probably need no changes. If you use
      a custom CA in your company then there are two ways to setup the CA
      certificates.</para>

      <section>
        <title>Setup SSL certificates in LAM general settings</title>

        <para>This is much easier than system level setup and will only affect
        LAM. There might be some cases where other web applications on the
        same web server are influenced.</para>

        <para>See <link linkend="conf_sslCert">here</link> for details.</para>
      </section>

      <section id="ssl_certSystem">
        <title>Setup SSL certificates on system level</title>

        <para>This will make the CA certificates available also to other
        applications on your system (e.g. other web applications).</para>

        <para>You will need to setup ldap.conf to trust your server
        certificate. Some installations use /etc/ldap.conf and some use
        /etc/ldap/ldap.conf. It is a good idea to symlink /etc/ldap.conf to
        /etc/ldap/ldap.conf. Specify the server CA certificate with the
        following option:</para>

        <programlisting>TLS_CACERT /etc/ldap/ca/myCA/cacert.pem</programlisting>

        <para>This needs to be the public part of the signing certificate
        authority. See "man ldap.conf" for additional options.</para>

        <literallayout>
</literallayout>

        <para>You may also need to specify the CA certificate in your Apache
        configuration by using the option "LDAPTrustedGlobalCert":</para>

        <programlisting>LDAPTrustedGlobalCert CA_BASE64 /etc/ldap/ca/myCA/cacert.pem</programlisting>
      </section>
    </section>

    <section id="selinux">
      <title>Selinux</title>

      <para>In case your server has selinux installed you might need to extend
      the selinux ruleset. E.g. your webserver might not be allowed to write
      in /var/lib.</para>

      <para><emphasis role="bold">Read selinux status</emphasis></para>

      <para>The following command will tell you if selinux is running in
      Enforcing or Permissive mode.</para>

      <para>Enforcing: access that does not match rules is denied</para>

      <para>Permissive: access that does not match rules is granted but logged
      to audit.log</para>

      <programlisting>getenforce</programlisting>

      <para><emphasis role="bold">Set selinux to Permissive
      mode</emphasis></para>

      <para>This will just log any access violations. You will need this to
      get a list of missing rights.</para>

      <programlisting>setenforce Permissive</programlisting>

      <para>Now do any actions inside LAM that you need for your daily work
      (e.g. edit server profiles, manage LDAP entries, ...).</para>

      <para><emphasis role="bold">Extend selinux rules</emphasis></para>

      <para>Selinux now has logged any violations to audit.log. You can use
      this now to extend your ruleset and enable enforcing later.</para>

      <para>The following example is for httpd. You can also adapt it to e.g.
      nginx.</para>

      <programlisting># build additional selinux rules from audit.log
grep httpd /var/log/audit/audit.log | audit2allow -m httpdlocal -o httpdlocal.te
</programlisting>

      <para>The httpdlocal.te might look like this:</para>

      <programlisting>module httpdlocal 1.0;

require {
        type httpd_t;
        type var_lib_t;
        class file { setattr write };
}

#============= httpd_t ==============

#!!!! WARNING 'httpd_t' is not allowed to write or create to var_lib_t.  Change the label to httpd_var_lib_t.
#!!!! $ semanage fcontext -a -t httpd_var_lib_t /var/lib/ldap-account-manager/config/lam.conf   
#!!!! $ restorecon -R -v /var/lib/ldap-account-manager/config/lam.conf
allow httpd_t var_lib_t:file { setattr write };
</programlisting>

      <para>Now we can compile and install this rule:</para>

      <programlisting># build module
checkmodule -M -m -o httpdlocal.mod httpdlocal.te
# package module
semodule_package -o httpdlocal.pp -m httpdlocal.mod
# install module
semodule -i httpdlocal.pp</programlisting>

      <para>Now you can switch back to Enforcing mode:</para>

      <programlisting>setenforce Enforcing</programlisting>

      <para>LAM should now work as expected with active selinux.</para>
    </section>

    <section>
      <title>Chrooted servers</title>

      <para>If your server is chrooted and you have no access to /dev/random
      or /dev/urandom this can be a security risk. LAM stores your LDAP
      password encrypted in the session. LAM uses rand() to generate the key
      if /dev/random and /dev/urandom are not accessible. Therefore the key
      can be easily guessed. An attaker needs read access to the session file
      (e.g. by another Apache instance) to exploit this.</para>
    </section>

    <section>
      <title>Protection of your LDAP password and directory contents</title>

      <para>You have to install the MCrypt extension for PHP to enable
      encryption.</para>

      <para>Your LDAP password is stored encrypted in the session file. The
      key and IV to decrypt it are stored in two cookies. We use MCrypt/AES to
      encrypt the password. All data that was read from LDAP and needs to be
      stored in the session file is also encrypted.</para>
    </section>

    <section id="apache">
      <title>Apache configuration</title>

      <section>
        <title>Sensitive directories</title>

        <para>LAM includes several .htaccess files to protect your
        configuration files and temporary data. Apache is often configured to
        not use .htaccess files by default. Therefore, please check your
        Apache configuration and change the override setting to:</para>

        <para>AllowOverride All</para>

        <para>If you are experienced in configuring Apache then you can also
        copy the security settings from the .htaccess files to your main
        Apache configuration.</para>

        <para>If possible, you should not rely on .htaccess files but also
        move the config and sess directory to a place outside of your WWW
        root. You can put a symbolic link in the LAM directory so that LAM
        finds the configuration/session files.</para>

        <para>Security sensitive directories:</para>

        <para><emphasis role="bold">config: </emphasis>Contains your LAM
        configuration and account profiles</para>

        <itemizedlist>
          <listitem>
            <para>LAM configuration passwords (SSHA hashed)</para>
          </listitem>

          <listitem>
            <para>default values for new accounts</para>
          </listitem>

          <listitem>
            <para>directory must be accessibly by Apache but needs not to be
            accessible by the browser</para>
          </listitem>
        </itemizedlist>

        <para><emphasis role="bold">sess:</emphasis> PHP session files</para>

        <itemizedlist>
          <listitem>
            <para>LAM admin password in clear text or MCrypt encrypted</para>
          </listitem>

          <listitem>
            <para>cached LDAP entries in clear text or MCrypt encrypted</para>
          </listitem>

          <listitem>
            <para>directory must be accessibly by Apache but needs not to be
            accessible by the browser</para>
          </listitem>
        </itemizedlist>

        <para><emphasis role="bold">tmp:</emphasis> temporary files</para>

        <itemizedlist>
          <listitem>
            <para>PDF documents which may also include passwords</para>
          </listitem>

          <listitem>
            <para>images of your users</para>
          </listitem>

          <listitem>
            <para>directory contents must be accessible by browser but
            directory itself needs not to be browseable</para>
          </listitem>
        </itemizedlist>
      </section>

      <section id="apache_http_auth">
        <title>Use LDAP HTTP authentication for LAM</title>

        <para>With HTTP authentication Apache will be responsible to ask for
        the user name and password. Both will then be forwarded to LAM which
        will use it to access LDAP. This approach gives you more flexibility
        to restrict the number of users that may access LAM (e.g. by requiring
        group memberships).</para>

        <para>First of all you need to load additional Apache modules. These
        are "<ulink
        url="http://httpd.apache.org/docs/2.2/mod/mod_ldap.html">mod_ldap</ulink>"
        and "<ulink type=""
        url="http://httpd.apache.org/docs/2.2/mod/mod_authnz_ldap.html">mod_authnz_ldap</ulink>".</para>

        <para>Next you can add a file called "lam_auth_ldap" to
        /etc/apache/conf.d. This simple example restricts access to all URLs
        beginning with "lam" to LDAP authentication.</para>

        <programlisting>&lt;location /lam&gt;
  AuthType Basic
  AuthBasicProvider ldap
  AuthName "LAM"
  AuthLDAPURL "ldap://localhost:389/ou=People,dc=company,dc=com?uid"
  Require valid-user
&lt;/location&gt;</programlisting>

        <para>You can also require that your users belong to a certain Unix
        group in LDAP:</para>

        <programlisting>&lt;location /lam&gt;
  AuthType Basic
  AuthBasicProvider ldap
  AuthName "LAM"
  AuthLDAPURL "ldap://localhost:389/ou=People,dc=company,dc=com?uid"
  Require valid-user
  # force membership of lam-admins
  AuthLDAPGroupAttribute memberUid
  AuthLDAPGroupAttributeIsDN off
  Require ldap-group cn=lam-admins,ou=group,dc=company,dc=com
&lt;/location&gt;</programlisting>

        <para>Please see the <ulink
        url="http://httpd.apache.org/docs/2.2/mod/mod_authnz_ldap.html">Apache
        documentation</ulink> for more details.</para>
      </section>

      <section>
        <title>Self Service behind proxy in DMZ (LAM Pro)</title>

        <para>In some cases you might want to make the self service accessible
        via the internet. Here is an Apache config to forward only the
        required URLs via a proxy server (lamproxy.company.com) in your DMZ to
        the internal LAM server (lam.company.com).</para>

        <para><inlinemediaobject>
            <imageobject>
              <imagedata fileref="images/selfServiceProxy.png" />
            </imageobject>
          </inlinemediaobject></para>

        <para>This configuration allows your users to open
        https://lamproxy.company.com which will then proxy the self service on
        the internal server.</para>

        <programlisting>&lt;VirtualHost lamproxy.company.com:443&gt;
        ServerName lamproxy.company.com
        ErrorLog /var/log/apache2/lam-proxy-error.log
        CustomLog /var/log/apache2/lam-proxy-access.log combined
        DocumentRoot /var/www/lam-proxy
        &lt;Proxy *&gt;
            Order deny,allow
            Allow from all
        &lt;/Proxy&gt;
        SSLProxyEngine on
        SSLEngine on
        SSLCertificateFile /etc/apache2/ssl/apache.pem
        ProxyPreserveHost On
        ProxyRequests off
        loglevel info

        # redirect front page to self service login page
        RewriteEngine on
        RedirectMatch ^/$ /templates/selfService/selfServiceLogin.php?scope=user\&amp;name=lam

        # proxy required URLs
        ProxyPass /tmp https://lam.company.com/lam/tmp
        ProxyPass /sess https://lam.company.com/lam/sess
        ProxyPass /templates/lib https://lam.company.com/lam/templates/lib
        ProxyPass /templates/selfService https://lam.company.com/lam/templates/selfService
        ProxyPass /style https://lam.company.com/lam/style
        ProxyPass /graphics https://lam.company.com/lam/graphics

        ProxyPassReverse /tmp https://lam.company.com/lam/tmp
        ProxyPassReverse /sess https://lam.company.com/lam/sess
        ProxyPassReverse /templates/lib https://lam.company.com/lam/templates/lib
        ProxyPassReverse /templates/selfService https://lam.company.com/lam/templates/selfService
        ProxyPassReverse /style https://lam.company.com/lam/style
        ProxyPassReverse /graphics https://lam.company.com/lam/graphics
&lt;/VirtualHost&gt;</programlisting>
      </section>
    </section>

    <section id="nginx">
      <title>Nginx configuration</title>

      <para>There is no fully automatic setup of Nginx but LAM provides a
      ready-to-use configuration file.</para>

      <section>
        <title>RPM based installations</title>

        <para>The RPM package has dependencies on Apache. Therefore, Nginx is
        not officially supported with this installation mode. Use tar.bz2 if
        you are unsure.</para>

        <para>However, the package also includes an Nginx configuration file.
        Please include it in your server directive like this:</para>

        <programlisting>server {
        ...

        include /etc/ldap-account-manager/lam.nginx.conf;

        ...
}</programlisting>
      </section>

      <section>
        <title>DEB based installations</title>

        <para>The LAM installation package ships with an Nginx configuration
        file. Please include it in your server directive like this:</para>

        <programlisting>server {
        ...

        include /etc/ldap-account-manager/lam.nginx.conf;

        ...
}</programlisting>
      </section>

      <section>
        <title>tar.bz2 based installations</title>

        <para>Please add the following configuration snippet to your server
        directive.</para>

        <para>You will need to change the alias location
        ("/usr/share/ldap-account-manager") and fastcgi_pass
        ("/var/run/php5-fpm.sock") to match your installation.</para>

        <programlisting>location /lam {
  index index.html;
  alias /usr/share/ldap-account-manager;
  autoindex off;

  location ~ \.php$ {
    fastcgi_split_path_info ^(.+\.php)(/.+)$;
    fastcgi_pass unix:/var/run/php5-fpm.sock;
    fastcgi_index index.php;
    include fastcgi_params;
  }

  location ~ /lam/(tmp/internal|sess|config|lib|help|locale) {
    deny all;
    return 403;
  }

}
</programlisting>
      </section>
    </section>
  </appendix>