Security warning: Couldn't write .htaccess file

Issue

As an Acquia Cloud Site Factory customer, I am receiving the following security warning on my server:

Security warning: Couldn't write .htaccess file. Please create a .htaccess file in your /mnt/www/html/site_env/docroot/sites/g/files/filename/files/config_xxxxxx/sync directory which contains the following lines:

# 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>

# 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_2006_003
<Files>

# If we know how to do it safely, disable the PHP engine entirely.
<IfModule mod_php5.c>
  php_flag engine off 
</IfModule>

Resolution

If you are receiving the above security warning on your server, you may need to set your configuration directories to be writable in a factory hook by using the following code snippet in a file such as acsf-config.php:

<?php 

/**
 *   Set vcs and sync dirs to writable directories above docroot.
 */

 $config_directories['vcs'] = '../config/default';
 $config_directories['sync'] = '../config/default';