diff --git a/core/composer.json b/core/composer.json
index 5d248a188e6a860988610f7de8b7de662227f812..f2440a73dec2186757263b1dd1e0f57437db96f3 100644
--- a/core/composer.json
+++ b/core/composer.json
@@ -85,6 +85,7 @@
         "drupal/core-discovery": "self.version",
         "drupal/core-event-dispatcher": "self.version",
         "drupal/core-file-cache": "self.version",
+        "drupal/core-file-security": "self.version",
         "drupal/core-filesystem": "self.version",
         "drupal/core-gettext": "self.version",
         "drupal/core-graph": "self.version",
diff --git a/core/includes/file.inc b/core/includes/file.inc
index c246fe402f189a2571b58da0a777c28c124f25ee..edbd86c53faffef70b9e43353f034f618822f846 100644
--- a/core/includes/file.inc
+++ b/core/includes/file.inc
@@ -5,8 +5,8 @@
  * API for handling file uploads and server file management.
  */
 
+use Drupal\Component\FileSecurity\FileSecurity;
 use Drupal\Component\FileSystem\FileSystem as ComponentFileSystem;
-use Drupal\Component\PhpStorage\FileStorage;
 use Drupal\Component\Utility\Environment;
 use Drupal\Component\Utility\UrlHelper;
 use Drupal\Core\File\Exception\FileException;
@@ -362,28 +362,18 @@ function file_save_htaccess($directory, $private = TRUE, $force_overwrite = FALS
   $stream_wrapper_manager = \Drupal::service('stream_wrapper_manager');
 
   if ($stream_wrapper_manager::getScheme($directory)) {
-    $htaccess_path = $stream_wrapper_manager->normalizeUri($directory . '/.htaccess');
+    $directory = $stream_wrapper_manager->normalizeUri($directory);
   }
   else {
     $directory = rtrim($directory, '/\\');
-    $htaccess_path = $directory . '/.htaccess';
   }
 
-  if (file_exists($htaccess_path) && !$force_overwrite) {
-    // Short circuit if the .htaccess file already exists.
+  if (FileSecurity::writeHtaccess($directory, $private, $force_overwrite)) {
     return TRUE;
   }
-  $htaccess_lines = FileStorage::htaccessLines($private);
 
-  // Write the .htaccess file.
-  if (file_exists($directory) && is_writable($directory) && file_put_contents($htaccess_path, $htaccess_lines)) {
-    return \Drupal::service('file_system')->chmod($htaccess_path, 0444);
-  }
-  else {
-    $variables = ['%directory' => $directory, '@htaccess' => $htaccess_lines];
-    \Drupal::logger('security')->error("Security warning: Couldn't write .htaccess file. Please create a .htaccess file in your %directory directory which contains the following lines: <pre><code>@htaccess</code></pre>", $variables);
-    return FALSE;
-  }
+  \Drupal::logger('security')->error("Security warning: Couldn't write .htaccess file. Please create a .htaccess file in your %directory directory which contains the following lines: <pre><code>@htaccess</code></pre>", ['%directory' => $directory, '@htaccess' => FileSecurity::htaccessLines($private)]);
+  return FALSE;
 }
 
 /**
@@ -398,12 +388,12 @@ function file_save_htaccess($directory, $private = TRUE, $force_overwrite = FALS
  *   The desired contents of the .htaccess file.
  *
  * @deprecated in Drupal 8.0.x-dev and will be removed before Drupal 9.0.0.
- *   Use \Drupal\Component\PhpStorage\FileStorage::htaccessLines().
+ *   Use \Drupal\Component\FileSecurity\FileSecurity::htaccessLines().
  *
  * @see https://www.drupal.org/node/2418133
  */
 function file_htaccess_lines($private = TRUE) {
-  return FileStorage::htaccessLines($private);
+  return FileSecurity::htaccessLines($private);
 }
 
 /**
diff --git a/core/lib/Drupal/Component/FileSecurity/FileSecurity.php b/core/lib/Drupal/Component/FileSecurity/FileSecurity.php
new file mode 100644
index 0000000000000000000000000000000000000000..efe1119c2707aa01a0bb11e98042e796e79f0158
--- /dev/null
+++ b/core/lib/Drupal/Component/FileSecurity/FileSecurity.php
@@ -0,0 +1,160 @@
+<?php
+
+namespace Drupal\Component\FileSecurity;
+
+/**
+ * Provides file security functions.
+ */
+class FileSecurity {
+
+  /**
+   * Writes an .htaccess file in the given directory, if it doesn't exist.
+   *
+   * @param string $directory
+   *   The directory.
+   * @param bool $deny_public_access
+   *   (optional) Set to FALSE to ensure an .htaccess file for an open and
+   *   public directory. Default is TRUE.
+   * @param bool $force
+   *   (optional) Set to TRUE to force overwrite an existing file.
+   *
+   * @return bool
+   *   TRUE if the file already exists or was created. FALSE otherwise.
+   */
+  public static function writeHtaccess($directory, $deny_public_access = TRUE, $force = FALSE) {
+    return self::writeFile($directory, '/.htaccess', self::htaccessLines($deny_public_access), $force);
+  }
+
+  /**
+   * Returns the standard .htaccess lines that Drupal writes.
+   *
+   * @param bool $deny_public_access
+   *   (optional) Set to FALSE to return the .htaccess lines for an open and
+   *   public directory that allows Apache to serve files, but not execute code.
+   *   The default is TRUE, which returns the .htaccess lines for a private and
+   *   protected directory that Apache will deny all access to.
+   *
+   * @return string
+   *   The desired contents of the .htaccess file.
+   *
+   * @see file_save_htaccess()
+   */
+  public static function htaccessLines($deny_public_access = TRUE) {
+    $lines = static::htaccessPreventExecution();
+
+    if ($deny_public_access) {
+      $lines = static::denyPublicAccess() . "\n\n$lines";
+    }
+
+    return $lines;
+  }
+
+  /**
+   * Returns htaccess directives to deny execution in a given directory.
+   *
+   * @return string
+   *   Apache htaccess directives to prevent execution of files in a location.
+   */
+  protected static function htaccessPreventExecution() {
+    return <<<EOF
+# Turn off all options we don't need.
+Options -Indexes -ExecCGI -Includes -MultiViews
+
+# Set the catch-all handler to prevent scripts from being executed.
+SetHandler Drupal_Security_Do_Not_Remove_See_SA_2006_006
+<Files *>
+  # Override the handler again if we're run later in the evaluation list.
+  SetHandler Drupal_Security_Do_Not_Remove_See_SA_2013_003
+</Files>
+
+# If we know how to do it safely, disable the PHP engine entirely.
+<IfModule mod_php5.c>
+  php_flag engine off
+</IfModule>
+<IfModule mod_php7.c>
+  php_flag engine off
+</IfModule>
+EOF;
+  }
+
+  /**
+   * Returns htaccess directives to block all access to a given directory.
+   *
+   * @return string
+   *   Apache htaccess directives to block access to a location.
+   */
+  protected static function denyPublicAccess() {
+    return <<<EOF
+# Deny all requests from Apache 2.4+.
+<IfModule mod_authz_core.c>
+  Require all denied
+</IfModule>
+
+# Deny all requests from Apache 2.0-2.2.
+<IfModule !mod_authz_core.c>
+  Deny from all
+</IfModule>
+EOF;
+  }
+
+  /**
+   * Writes a web.config file in the given directory, if it doesn't exist.
+   *
+   * @param string $directory
+   *   The directory.
+   * @param bool $force
+   *   (optional) Set to TRUE to force overwrite an existing file.
+   *
+   * @return bool
+   *   TRUE if the file already exists or was created. FALSE otherwise.
+   */
+  public static function writeWebConfig($directory, $force = FALSE) {
+    return self::writeFile($directory, '/web.config', self::webConfigLines(), $force);
+  }
+
+  /**
+   * Returns the standard web.config lines for security.
+   *
+   * @return string
+   *   The contents of the web.config file.
+   */
+  public static function webConfigLines() {
+    return <<<EOT
+<configuration>
+  <system.webServer>
+    <authorization>
+      <deny users="*">
+    </authorization>
+  </system.webServer>
+</configuration>
+EOT;
+  }
+
+  /**
+   * Writes the contents to the file in the given directory.
+   *
+   * @param string $directory
+   *   The directory to write to.
+   * @param string $filename
+   *   The file name.
+   * @param string $contents
+   *   The file contents.
+   * @param bool $force
+   *   TRUE if we should force the write over an existing file.
+   *
+   * @return bool
+   *   TRUE if writing the file was successful.
+   */
+  protected static function writeFile($directory, $filename, $contents, $force) {
+    $file_path = $directory . DIRECTORY_SEPARATOR . $filename;
+    // Don't overwrite if the file exists unless forced.
+    if (file_exists($file_path) && !$force) {
+      return TRUE;
+    }
+    if (file_exists($directory) && is_writable($directory) && file_put_contents($file_path, $contents)) {
+      return @chmod($file_path, 0444);
+    }
+    return FALSE;
+  }
+
+}
diff --git a/core/lib/Drupal/Component/FileSecurity/LICENSE.txt b/core/lib/Drupal/Component/FileSecurity/LICENSE.txt
new file mode 100644
index 0000000000000000000000000000000000000000..94fb84639c4b6ff359e47a124d8fb4a3aba7a386
--- /dev/null
+++ b/core/lib/Drupal/Component/FileSecurity/LICENSE.txt
@@ -0,0 +1,339 @@
+        GNU GENERAL PUBLIC LICENSE
+           Version 2, June 1991
+
+ Copyright (C) 1989, 1991 Free Software Foundation, Inc.,
+ 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ Everyone is permitted to copy and distribute verbatim copies
+ of this license document, but changing it is not allowed.
+
+          Preamble
+
+  The licenses for most software are designed to take away your
+freedom to share and change it.  By contrast, the GNU General Public
+License is intended to guarantee your freedom to share and change free
+software--to make sure the software is free for all its users.  This
+General Public License applies to most of the Free Software
+Foundation's software and to any other program whose authors commit to
+using it.  (Some other Free Software Foundation software is covered by
+the GNU Lesser General Public License instead.)  You can apply it to
+your programs, too.
+
+  When we speak of free software, we are referring to freedom, not
+price.  Our General Public Licenses are designed to make sure that you
+have the freedom to distribute copies of free software (and charge for
+this service if you wish), that you receive source code or can get it
+if you want it, that you can change the software or use pieces of it
+in new free programs; and that you know you can do these things.
+
+  To protect your rights, we need to make restrictions that forbid
+anyone to deny you these rights or to ask you to surrender the rights.
+These restrictions translate to certain responsibilities for you if you
+distribute copies of the software, or if you modify it.
+
+  For example, if you distribute copies of such a program, whether
+gratis or for a fee, you must give the recipients all the rights that
+you have.  You must make sure that they, too, receive or can get the
+source code.  And you must show them these terms so they know their
+rights.
+
+  We protect your rights with two steps: (1) copyright the software, and
+(2) offer you this license which gives you legal permission to copy,
+distribute and/or modify the software.
+
+  Also, for each author's protection and ours, we want to make certain
+that everyone understands that there is no warranty for this free
+software.  If the software is modified by someone else and passed on, we
+want its recipients to know that what they have is not the original, so
+that any problems introduced by others will not reflect on the original
+authors' reputations.
+
+  Finally, any free program is threatened constantly by software
+patents.  We wish to avoid the danger that redistributors of a free
+program will individually obtain patent licenses, in effect making the
+program proprietary.  To prevent this, we have made it clear that any
+patent must be licensed for everyone's free use or not licensed at all.
+
+  The precise terms and conditions for copying, distribution and
+modification follow.
+
+        GNU GENERAL PUBLIC LICENSE
+   TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
+
+  0. This License applies to any program or other work which contains
+a notice placed by the copyright holder saying it may be distributed
+under the terms of this General Public License.  The "Program", below,
+refers to any such program or work, and a "work based on the Program"
+means either the Program or any derivative work under copyright law:
+that is to say, a work containing the Program or a portion of it,
+either verbatim or with modifications and/or translated into another
+language.  (Hereinafter, translation is included without limitation in
+the term "modification".)  Each licensee is addressed as "you".
+
+Activities other than copying, distribution and modification are not
+covered by this License; they are outside its scope.  The act of
+running the Program is not restricted, and the output from the Program
+is covered only if its contents constitute a work based on the
+Program (independent of having been made by running the Program).
+Whether that is true depends on what the Program does.
+
+  1. You may copy and distribute verbatim copies of the Program's
+source code as you receive it, in any medium, provided that you
+conspicuously and appropriately publish on each copy an appropriate
+copyright notice and disclaimer of warranty; keep intact all the
+notices that refer to this License and to the absence of any warranty;
+and give any other recipients of the Program a copy of this License
+along with the Program.
+
+You may charge a fee for the physical act of transferring a copy, and
+you may at your option offer warranty protection in exchange for a fee.
+
+  2. You may modify your copy or copies of the Program or any portion
+of it, thus forming a work based on the Program, and copy and
+distribute such modifications or work under the terms of Section 1
+above, provided that you also meet all of these conditions:
+
+    a) You must cause the modified files to carry prominent notices
+    stating that you changed the files and the date of any change.
+
+    b) You must cause any work that you distribute or publish, that in
+    whole or in part contains or is derived from the Program or any
+    part thereof, to be licensed as a whole at no charge to all third
+    parties under the terms of this License.
+
+    c) If the modified program normally reads commands interactively
+    when run, you must cause it, when started running for such
+    interactive use in the most ordinary way, to print or display an
+    announcement including an appropriate copyright notice and a
+    notice that there is no warranty (or else, saying that you provide
+    a warranty) and that users may redistribute the program under
+    these conditions, and telling the user how to view a copy of this
+    License.  (Exception: if the Program itself is interactive but
+    does not normally print such an announcement, your work based on
+    the Program is not required to print an announcement.)
+
+These requirements apply to the modified work as a whole.  If
+identifiable sections of that work are not derived from the Program,
+and can be reasonably considered independent and separate works in
+themselves, then this License, and its terms, do not apply to those
+sections when you distribute them as separate works.  But when you
+distribute the same sections as part of a whole which is a work based
+on the Program, the distribution of the whole must be on the terms of
+this License, whose permissions for other licensees extend to the
+entire whole, and thus to each and every part regardless of who wrote it.
+
+Thus, it is not the intent of this section to claim rights or contest
+your rights to work written entirely by you; rather, the intent is to
+exercise the right to control the distribution of derivative or
+collective works based on the Program.
+
+In addition, mere aggregation of another work not based on the Program
+with the Program (or with a work based on the Program) on a volume of
+a storage or distribution medium does not bring the other work under
+the scope of this License.
+
+  3. You may copy and distribute the Program (or a work based on it,
+under Section 2) in object code or executable form under the terms of
+Sections 1 and 2 above provided that you also do one of the following:
+
+    a) Accompany it with the complete corresponding machine-readable
+    source code, which must be distributed under the terms of Sections
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+
+    b) Accompany it with a written offer, valid for at least three
+    years, to give any third party, for a charge no more than your
+    cost of physically performing source distribution, a complete
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+    distributed under the terms of Sections 1 and 2 above on a medium
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+
+    c) Accompany it with the information you received as to the offer
+    to distribute corresponding source code.  (This alternative is
+    allowed only for noncommercial distribution and only if you
+    received the program in object code or executable form with such
+    an offer, in accord with Subsection b above.)
+
+The source code for a work means the preferred form of the work for
+making modifications to it.  For an executable work, complete source
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+associated interface definition files, plus the scripts used to
+control compilation and installation of the executable.  However, as a
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+anything that is normally distributed (in either source or binary
+form) with the major components (compiler, kernel, and so on) of the
+operating system on which the executable runs, unless that component
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+
+If distribution of executable or object code is made by offering
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+access to copy the source code from the same place counts as
+distribution of the source code, even though third parties are not
+compelled to copy the source along with the object code.
+
+  4. You may not copy, modify, sublicense, or distribute the Program
+except as expressly provided under this License.  Any attempt
+otherwise to copy, modify, sublicense or distribute the Program is
+void, and will automatically terminate your rights under this License.
+However, parties who have received copies, or rights, from you under
+this License will not have their licenses terminated so long as such
+parties remain in full compliance.
+
+  5. You are not required to accept this License, since you have not
+signed it.  However, nothing else grants you permission to modify or
+distribute the Program or its derivative works.  These actions are
+prohibited by law if you do not accept this License.  Therefore, by
+modifying or distributing the Program (or any work based on the
+Program), you indicate your acceptance of this License to do so, and
+all its terms and conditions for copying, distributing or modifying
+the Program or works based on it.
+
+  6. Each time you redistribute the Program (or any work based on the
+Program), the recipient automatically receives a license from the
+original licensor to copy, distribute or modify the Program subject to
+these terms and conditions.  You may not impose any further
+restrictions on the recipients' exercise of the rights granted herein.
+You are not responsible for enforcing compliance by third parties to
+this License.
+
+  7. If, as a consequence of a court judgment or allegation of patent
+infringement or for any other reason (not limited to patent issues),
+conditions are imposed on you (whether by court order, agreement or
+otherwise) that contradict the conditions of this License, they do not
+excuse you from the conditions of this License.  If you cannot
+distribute so as to satisfy simultaneously your obligations under this
+License and any other pertinent obligations, then as a consequence you
+may not distribute the Program at all.  For example, if a patent
+license would not permit royalty-free redistribution of the Program by
+all those who receive copies directly or indirectly through you, then
+the only way you could satisfy both it and this License would be to
+refrain entirely from distribution of the Program.
+
+If any portion of this section is held invalid or unenforceable under
+any particular circumstance, the balance of the section is intended to
+apply and the section as a whole is intended to apply in other
+circumstances.
+
+It is not the purpose of this section to induce you to infringe any
+patents or other property right claims or to contest validity of any
+such claims; this section has the sole purpose of protecting the
+integrity of the free software distribution system, which is
+implemented by public license practices.  Many people have made
+generous contributions to the wide range of software distributed
+through that system in reliance on consistent application of that
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+to distribute software through any other system and a licensee cannot
+impose that choice.
+
+This section is intended to make thoroughly clear what is believed to
+be a consequence of the rest of this License.
+
+  8. If the distribution and/or use of the Program is restricted in
+certain countries either by patents or by copyrighted interfaces, the
+original copyright holder who places the Program under this License
+may add an explicit geographical distribution limitation excluding
+those countries, so that distribution is permitted only in or among
+countries not thus excluded.  In such case, this License incorporates
+the limitation as if written in the body of this License.
+
+  9. The Free Software Foundation may publish revised and/or new versions
+of the General Public License from time to time.  Such new versions will
+be similar in spirit to the present version, but may differ in detail to
+address new problems or concerns.
+
+Each version is given a distinguishing version number.  If the Program
+specifies a version number of this License which applies to it and "any
+later version", you have the option of following the terms and conditions
+either of that version or of any later version published by the Free
+Software Foundation.  If the Program does not specify a version number of
+this License, you may choose any version ever published by the Free Software
+Foundation.
+
+  10. If you wish to incorporate parts of the Program into other free
+programs whose distribution conditions are different, write to the author
+to ask for permission.  For software which is copyrighted by the Free
+Software Foundation, write to the Free Software Foundation; we sometimes
+make exceptions for this.  Our decision will be guided by the two goals
+of preserving the free status of all derivatives of our free software and
+of promoting the sharing and reuse of software generally.
+
+          NO WARRANTY
+
+  11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY
+FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW.  EXCEPT WHEN
+OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES
+PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED
+OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.  THE ENTIRE RISK AS
+TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU.  SHOULD THE
+PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING,
+REPAIR OR CORRECTION.
+
+  12. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
+WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR
+REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES,
+INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING
+OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED
+TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY
+YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER
+PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGES.
+
+         END OF TERMS AND CONDITIONS
+
+      How to Apply These Terms to Your New Programs
+
+  If you develop a new program, and you want it to be of the greatest
+possible use to the public, the best way to achieve this is to make it
+free software which everyone can redistribute and change under these terms.
+
+  To do so, attach the following notices to the program.  It is safest
+to attach them to the start of each source file to most effectively
+convey the exclusion of warranty; and each file should have at least
+the "copyright" line and a pointer to where the full notice is found.
+
+    <one line to give the program's name and a brief idea of what it does.>
+    Copyright (C) <year>  <name of author>
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License along
+    with this program; if not, write to the Free Software Foundation, Inc.,
+    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+
+Also add information on how to contact you by electronic and paper mail.
+
+If the program is interactive, make it output a short notice like this
+when it starts in an interactive mode:
+
+    Gnomovision version 69, Copyright (C) year name of author
+    Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
+    This is free software, and you are welcome to redistribute it
+    under certain conditions; type `show c' for details.
+
+The hypothetical commands `show w' and `show c' should show the appropriate
+parts of the General Public License.  Of course, the commands you use may
+be called something other than `show w' and `show c'; they could even be
+mouse-clicks or menu items--whatever suits your program.
+
+You should also get your employer (if you work as a programmer) or your
+school, if any, to sign a "copyright disclaimer" for the program, if
+necessary.  Here is a sample; alter the names:
+
+  Yoyodyne, Inc., hereby disclaims all copyright interest in the program
+  `Gnomovision' (which makes passes at compilers) written by James Hacker.
+
+  <signature of Ty Coon>, 1 April 1989
+  Ty Coon, President of Vice
+
+This General Public License does not permit incorporating your program into
+proprietary programs.  If your program is a subroutine library, you may
+consider it more useful to permit linking proprietary applications with the
+library.  If this is what you want to do, use the GNU Lesser General
+Public License instead of this License.
diff --git a/core/lib/Drupal/Component/FileSecurity/README.txt b/core/lib/Drupal/Component/FileSecurity/README.txt
new file mode 100644
index 0000000000000000000000000000000000000000..a63fc780f8d75c74fa67b90de3bf4b92dd35ff0d
--- /dev/null
+++ b/core/lib/Drupal/Component/FileSecurity/README.txt
@@ -0,0 +1,12 @@
+The Drupal FileSecurity Component
+
+Thanks for using this Drupal component.
+
+You can participate in its development on Drupal.org, through our issue system:
+https://www.drupal.org/project/issues/drupal
+
+You can get the full Drupal repo here:
+https://www.drupal.org/project/drupal/git-instructions
+
+You can browse the full Drupal repo here:
+http://cgit.drupalcode.org/drupal
diff --git a/core/lib/Drupal/Component/FileSecurity/TESTING.txt b/core/lib/Drupal/Component/FileSecurity/TESTING.txt
new file mode 100644
index 0000000000000000000000000000000000000000..3def769ff5d0d6e5d63f5c308c428a32c8136c5d
--- /dev/null
+++ b/core/lib/Drupal/Component/FileSecurity/TESTING.txt
@@ -0,0 +1,18 @@
+HOW-TO: Test this Drupal component
+
+In order to test this component, you'll need to get the entire Drupal repo and
+run the tests there.
+
+You'll find the tests under core/tests/Drupal/Tests/Component.
+
+You can get the full Drupal repo here:
+https://www.drupal.org/project/drupal/git-instructions
+
+You can find more information about running PHPUnit tests with Drupal here:
+https://www.drupal.org/node/2116263
+
+Each component in the Drupal\Component namespace has its own annotated test
+group. You can use this group to run only the tests for this component. Like
+this:
+
+$ ./vendor/bin/phpunit -c core --group FileSecurity
diff --git a/core/lib/Drupal/Component/FileSecurity/composer.json b/core/lib/Drupal/Component/FileSecurity/composer.json
new file mode 100644
index 0000000000000000000000000000000000000000..039431346895ba2c1e085991f5a232b87404037c
--- /dev/null
+++ b/core/lib/Drupal/Component/FileSecurity/composer.json
@@ -0,0 +1,15 @@
+{
+  "name": "drupal/core-file-security",
+  "description": "FileSecurity.",
+  "keywords": ["drupal"],
+  "homepage": "https://www.drupal.org/project/drupal",
+  "license": "GPL-2.0-or-later",
+  "require": {
+    "php": ">=7.0.8"
+  },
+  "autoload": {
+    "psr-4": {
+      "Drupal\\Component\\FileSecurity\\": ""
+    }
+  }
+}
diff --git a/core/lib/Drupal/Component/PhpStorage/FileStorage.php b/core/lib/Drupal/Component/PhpStorage/FileStorage.php
index d00d2779e523117765b0e1692f44c67b272a3008..0486eb356964f5738ec5910a4b468ee58290b233 100644
--- a/core/lib/Drupal/Component/PhpStorage/FileStorage.php
+++ b/core/lib/Drupal/Component/PhpStorage/FileStorage.php
@@ -2,6 +2,8 @@
 
 namespace Drupal\Component\PhpStorage;
 
+use Drupal\Component\FileSecurity\FileSecurity;
+
 /**
  * Stores the code as regular PHP files.
  */
@@ -64,46 +66,15 @@ public function save($name, $code) {
    * @return string
    *   The desired contents of the .htaccess file.
    *
-   * @see file_create_htaccess()
+   * @deprecated in drupal:8.8.0 and is removed from drupal:9.0.0. Instead use
+   *   \Drupal\Component\FileSecurity\FileSecurity.
+   *
+   * @see https://www.drupal.org/node/3075098
+   * @see file_save_htaccess()
    */
   public static function htaccessLines($private = TRUE) {
-    $lines = <<<EOF
-# Turn off all options we don't need.
-Options -Indexes -ExecCGI -Includes -MultiViews
-
-# Set the catch-all handler to prevent scripts from being executed.
-SetHandler Drupal_Security_Do_Not_Remove_See_SA_2006_006
-<Files *>
-  # Override the handler again if we're run later in the evaluation list.
-  SetHandler Drupal_Security_Do_Not_Remove_See_SA_2013_003
-</Files>
-
-# If we know how to do it safely, disable the PHP engine entirely.
-<IfModule mod_php5.c>
-  php_flag engine off
-</IfModule>
-<IfModule mod_php7.c>
-  php_flag engine off
-</IfModule>
-EOF;
-
-    if ($private) {
-      $lines = <<<EOF
-# Deny all requests from Apache 2.4+.
-<IfModule mod_authz_core.c>
-  Require all denied
-</IfModule>
-
-# Deny all requests from Apache 2.0-2.2.
-<IfModule !mod_authz_core.c>
-  Deny from all
-</IfModule>
-
-$lines
-EOF;
-    }
-
-    return $lines;
+    @trigger_error("htaccessLines() is deprecated in drupal:8.8.0 and is removed from drupal:9.0.0. Use \Drupal\Component\FileSecurity\FileSecurity::htaccessLines() instead. See https://www.drupal.org/node/3075098", E_USER_DEPRECATED);
+    return FileSecurity::htaccessLines($private);
   }
 
   /**
@@ -122,10 +93,7 @@ public static function htaccessLines($private = TRUE) {
    */
   protected function ensureDirectory($directory, $mode = 0777) {
     if ($this->createDirectory($directory, $mode)) {
-      $htaccess_path = $directory . '/.htaccess';
-      if (!file_exists($htaccess_path) && file_put_contents($htaccess_path, static::htaccessLines())) {
-        @chmod($htaccess_path, 0444);
-      }
+      FileSecurity::writeHtaccess($directory);
     }
   }
 
diff --git a/core/lib/Drupal/Component/PhpStorage/composer.json b/core/lib/Drupal/Component/PhpStorage/composer.json
index e4ff9b69be2f440e333cf5f484b431c968d79838..e2ed734ca4a4c98e2952c0e5d24447523158db3c 100644
--- a/core/lib/Drupal/Component/PhpStorage/composer.json
+++ b/core/lib/Drupal/Component/PhpStorage/composer.json
@@ -5,7 +5,8 @@
   "homepage": "https://www.drupal.org/project/drupal",
   "license": "GPL-2.0-or-later",
   "require": {
-    "php": ">=7.0.8"
+    "php": ">=7.0.8",
+    "drupal/core-file-security": "^8.8"
   },
   "autoload": {
     "psr-4": {
diff --git a/core/lib/Drupal/Core/Composer/Composer.php b/core/lib/Drupal/Core/Composer/Composer.php
index 4119089a66a8821dec2069fb9f7ded845344a6ab..8a3bd28d3f5f86a51f6c2329fbc5f8f9537a27e9 100644
--- a/core/lib/Drupal/Core/Composer/Composer.php
+++ b/core/lib/Drupal/Core/Composer/Composer.php
@@ -2,13 +2,13 @@
 
 namespace Drupal\Core\Composer;
 
-use Drupal\Component\PhpStorage\FileStorage;
-use Composer\Semver\Comparator;
 use Composer\Composer as ComposerApp;
-use Composer\Script\Event;
 use Composer\Installer\PackageEvent;
+use Composer\Script\Event;
+use Composer\Semver\Comparator;
 use Composer\Semver\Constraint\Constraint;
 use Composer\Util\ProcessExecutor;
+use Drupal\Component\FileSecurity\FileSecurity;
 
 /**
  * Provides static functions for composer script events.
@@ -162,25 +162,10 @@ public static function ensureHtaccess(Event $event) {
     $vendor_dir = $event->getComposer()->getConfig()->get('vendor-dir');
 
     // Prevent access to vendor directory on Apache servers.
-    $htaccess_file = $vendor_dir . '/.htaccess';
-    if (!file_exists($htaccess_file)) {
-      file_put_contents($htaccess_file, FileStorage::htaccessLines(TRUE) . "\n");
-    }
+    FileSecurity::writeHtaccess($vendor_dir);
 
     // Prevent access to vendor directory on IIS servers.
-    $webconfig_file = $vendor_dir . '/web.config';
-    if (!file_exists($webconfig_file)) {
-      $lines = <<<EOT
-<configuration>
-  <system.webServer>
-    <authorization>
-      <deny users="*">
-    </authorization>
-  </system.webServer>
-</configuration>
-EOT;
-      file_put_contents($webconfig_file, $lines . "\n");
-    }
+    FileSecurity::writeWebConfig($vendor_dir);
   }
 
   /**
diff --git a/core/modules/system/tests/src/Functional/File/FileSaveHtaccessLoggingTest.php b/core/modules/system/tests/src/Functional/File/FileSaveHtaccessLoggingTest.php
index 003373de718e5f310ae40126e1febf04669265a3..a75952d9088a883bc0a67d6ecaadbecc0154c934 100644
--- a/core/modules/system/tests/src/Functional/File/FileSaveHtaccessLoggingTest.php
+++ b/core/modules/system/tests/src/Functional/File/FileSaveHtaccessLoggingTest.php
@@ -2,7 +2,7 @@
 
 namespace Drupal\Tests\system\Functional\File;
 
-use Drupal\Component\PhpStorage\FileStorage;
+use Drupal\Component\FileSecurity\FileSecurity;
 use Drupal\Tests\BrowserTestBase;
 
 /**
@@ -29,7 +29,7 @@ public function testHtaccessSave() {
     $this->drupalGet('admin/reports/dblog');
     $this->clickLink("Security warning: Couldn't write .htaccess file. Please…");
 
-    $lines = FileStorage::htaccessLines(TRUE);
+    $lines = FileSecurity::htaccessLines(TRUE);
     foreach (array_filter(explode("\n", $lines)) as $line) {
       $this->assertEscaped($line);
     }
diff --git a/core/tests/Drupal/KernelTests/Core/File/DirectoryTest.php b/core/tests/Drupal/KernelTests/Core/File/DirectoryTest.php
index 796e87b4d6d3e0832ffa4bdfcbeb6b05fbada1e3..c8834e7bd8d50696cec81781543038aacf419a71 100644
--- a/core/tests/Drupal/KernelTests/Core/File/DirectoryTest.php
+++ b/core/tests/Drupal/KernelTests/Core/File/DirectoryTest.php
@@ -2,9 +2,9 @@
 
 namespace Drupal\KernelTests\Core\File;
 
+use Drupal\Component\FileSecurity\FileSecurity;
 use Drupal\Component\FileSystem\FileSystem;
 use Drupal\Component\Render\FormattableMarkup;
-use Drupal\Component\PhpStorage\FileStorage;
 use Drupal\Core\File\Exception\FileException;
 use Drupal\Core\File\FileSystemInterface;
 
@@ -101,7 +101,7 @@ public function testFileCheckDirectoryHandling() {
     $this->assertTrue(is_file($default_scheme . '://.htaccess'), 'Successfully re-created the .htaccess file in the files directory.', 'File');
     // Verify contents of .htaccess file.
     $file = file_get_contents($default_scheme . '://.htaccess');
-    $this->assertEqual($file, FileStorage::htaccessLines(FALSE), 'The .htaccess file contains the proper content.', 'File');
+    $this->assertEqual($file, FileSecurity::htaccessLines(FALSE), 'The .htaccess file contains the proper content.', 'File');
   }
 
   /**
diff --git a/core/tests/Drupal/Tests/Component/FileSecurity/FileSecurityTest.php b/core/tests/Drupal/Tests/Component/FileSecurity/FileSecurityTest.php
new file mode 100644
index 0000000000000000000000000000000000000000..0066f53d7cf01181862070e558cc63a1f8bcf921
--- /dev/null
+++ b/core/tests/Drupal/Tests/Component/FileSecurity/FileSecurityTest.php
@@ -0,0 +1,96 @@
+<?php
+
+namespace Drupal\Tests\Component\FileSecurity;
+
+use Drupal\Component\FileSecurity\FileSecurity;
+use org\bovigo\vfs\vfsStream;
+use PHPUnit\Framework\TestCase;
+
+/**
+ * Tests the file security component.
+ *
+ * @coversDefaultClass \Drupal\Component\FileSecurity\FileSecurity
+ * @group FileSecurity
+ */
+class FileSecurityTest extends TestCase {
+
+  /**
+   * @covers ::writeHtaccess
+   */
+  public function testWriteHtaccessPrivate() {
+    vfsStream::setup('root');
+    FileSecurity::writeHtaccess(vfsStream::url('root'));
+    $htaccess_file = vfsStream::url('root') . '/.htaccess';
+    $this->assertFileExists($htaccess_file);
+    $this->assertEquals('0444', substr(sprintf('%o', fileperms($htaccess_file)), -4));
+    $htaccess_contents = file_get_contents($htaccess_file);
+    $this->assertContains("Require all denied", $htaccess_contents);
+  }
+
+  /**
+   * @covers ::writeHtaccess
+   */
+  public function testWriteHtaccessPublic() {
+    vfsStream::setup('root');
+    $this->assertTrue(FileSecurity::writeHtaccess(vfsStream::url('root'), FALSE));
+    $htaccess_file = vfsStream::url('root') . '/.htaccess';
+    $this->assertFileExists($htaccess_file);
+    $this->assertEquals('0444', substr(sprintf('%o', fileperms($htaccess_file)), -4));
+    $htaccess_contents = file_get_contents($htaccess_file);
+    $this->assertNotContains("Require all denied", $htaccess_contents);
+  }
+
+  /**
+   * @covers ::writeHtaccess
+   */
+  public function testWriteHtaccessForceOverwrite() {
+    vfsStream::setup('root');
+    $htaccess_file = vfsStream::url('root') . '/.htaccess';
+    file_put_contents($htaccess_file, "foo");
+    $this->assertTrue(FileSecurity::writeHtaccess(vfsStream::url('root'), TRUE, TRUE));
+    $htaccess_contents = file_get_contents($htaccess_file);
+    $this->assertContains("Require all denied", $htaccess_contents);
+    $this->assertNotContains("foo", $htaccess_contents);
+  }
+
+  /**
+   * @covers ::writeHtaccess
+   */
+  public function testWriteHtaccessFailure() {
+    vfsStream::setup('root');
+    $this->assertFalse(FileSecurity::writeHtaccess(vfsStream::url('root') . '/foo'));
+  }
+
+  /**
+   * @covers ::writeWebConfig
+   */
+  public function testWriteWebConfig() {
+    vfsStream::setup('root');
+    $this->assertTrue(FileSecurity::writeWebConfig(vfsStream::url('root')));
+    $web_config_file = vfsStream::url('root') . '/web.config';
+    $this->assertFileExists($web_config_file);
+    $this->assertEquals('0444', substr(sprintf('%o', fileperms($web_config_file)), -4));
+  }
+
+  /**
+   * @covers ::writeWebConfig
+   */
+  public function testWriteWebConfigForceOverwrite() {
+    vfsStream::setup('root');
+    $web_config_file = vfsStream::url('root') . '/web.config';
+    file_put_contents($web_config_file, "foo");
+    $this->assertTrue(FileSecurity::writeWebConfig(vfsStream::url('root'), TRUE));
+    $this->assertFileExists($web_config_file);
+    $this->assertEquals('0444', substr(sprintf('%o', fileperms($web_config_file)), -4));
+    $this->assertNotContains("foo", $web_config_file);
+  }
+
+  /**
+   * @covers ::writeWebConfig
+   */
+  public function testWriteWebConfigFailure() {
+    vfsStream::setup('root');
+    $this->assertFalse(FileSecurity::writeWebConfig(vfsStream::url('root') . '/foo'));
+  }
+
+}
diff --git a/core/tests/Drupal/Tests/Component/PhpStorage/FileStorageDeprecationTest.php b/core/tests/Drupal/Tests/Component/PhpStorage/FileStorageDeprecationTest.php
new file mode 100644
index 0000000000000000000000000000000000000000..7ca8c51955074399227fccf263427971736143e1
--- /dev/null
+++ b/core/tests/Drupal/Tests/Component/PhpStorage/FileStorageDeprecationTest.php
@@ -0,0 +1,25 @@
+<?php
+
+namespace Drupal\Tests\Component\PhpStorage;
+
+use Drupal\Component\PhpStorage\FileStorage;
+use PHPUnit\Framework\TestCase;
+
+/**
+ * Tests FileStorage deprecations.
+ *
+ * @coversDefaultClass \Drupal\Component\PhpStorage\FileStorage
+ * @group legacy
+ * @group Drupal
+ * @group PhpStorage
+ */
+class FileStorageDeprecationTest extends TestCase {
+
+  /**
+   * @expectedDeprecation htaccessLines() is deprecated in drupal:8.8.0 and is removed from drupal:9.0.0. Use \Drupal\Component\FileSecurity\FileSecurity::htaccessLines() instead. See https://www.drupal.org/node/3075098
+   */
+  public function testHtAccessLines() {
+    $this->assertNotEmpty(FileStorage::htaccessLines());
+  }
+
+}
diff --git a/core/tests/Drupal/Tests/Component/PhpStorage/MTimeProtectedFileStorageBase.php b/core/tests/Drupal/Tests/Component/PhpStorage/MTimeProtectedFileStorageBase.php
index 7c4b787c34234eb41f3304cf21cf63792f5ff92f..ad78951713d4b522d84d9d314dd641e77d00f0d0 100644
--- a/core/tests/Drupal/Tests/Component/PhpStorage/MTimeProtectedFileStorageBase.php
+++ b/core/tests/Drupal/Tests/Component/PhpStorage/MTimeProtectedFileStorageBase.php
@@ -2,6 +2,7 @@
 
 namespace Drupal\Tests\Component\PhpStorage;
 
+use Drupal\Component\FileSecurity\FileSecurity;
 use Drupal\Component\Utility\Crypt;
 use Drupal\Component\Utility\Random;
 
@@ -96,7 +97,7 @@ public function testSecurity() {
 
     // Ensure the root directory for the bin has a .htaccess file denying web
     // access.
-    $this->assertSame(file_get_contents($expected_root_directory . '/.htaccess'), call_user_func([$this->storageClass, 'htaccessLines']));
+    $this->assertSame(file_get_contents($expected_root_directory . '/.htaccess'), FileSecurity::htaccessLines());
 
     // Ensure that if the file is replaced with an untrusted one (due to another
     // script's file upload vulnerability), it does not get loaded. Since mtime