Apache 2 - Security

Apache 2 and PHP5: Secure your installation!

PHP Security Info

If you want to test your PHP security, you can use the PHPSecInfo tool, available at: http://phpsec.org/projects/phpsecinfo/index.html

Installation

cd /tmp
wget http://phpsec.org/projects/phpsecinfo/phpsecinfo.zip
unzip phpsecinfo.zip
mv phpsecinfo-Version phpsecinfo
mv phpsecinfo/ /var/www
cd /var/www
chown -R www-data:www-data phpsecinfo

Virtual host configuration

Edit your V.Host configuration

vim /etc/apache2/sites-available/myServer

!! For security reason: DO NOT use 'phpsecinfo' as alias. It's too easy to guess.

<VirtualHost _default_:443>
         # PHPSecInfo
         Alias   /phpsec   /var/www/phpsecinfo
         <Location /phpsec >
                 Require all granted
                 ProxyPass !
                 order deny,allow
                 # allow from 127.0.0.1 192.168.1.0/24
                 allow from all
          </Location>
</VirtualHost>

Reload your configuration

/etc/init.d/apache2 reload

Run the test

To asset your current installation you can run the test: https://myServer/phpsec

Improve security

PHP5 sessions and temp files

Create specific directory to store the sessions and temp files:

mkdir -p /etc/php5/temp
mkdir -p /etc/php5/session
chown -R www-data:root /etc/php5/temp
chown -R www-data:root /etc/php5/session
chmod -R 770 /etc/php5/session
chmod -R 770 /etc/php5/temp

Edit the configuration file

vim /etc/php5/apache2/php.ini

Adjust:

• line 801 → upload_tmp_dir = /etc/php5/temp
• line 1357 → session.save_path = "/etc/php5/session"

PHP5 tweak

Edit the configuration file

vim /etc/php5/apache2/php.ini

Adjust:

• line 376 → expose_php = Off
• line 406 → memory_limit = 8M
• line 480 → display_errors=Off
• line 675 → post_max_size=256K
• line 805 → upload_max_filesize=256K
• line 814 → allow_url_fopen=Off

 DO NOT enable the open_basedir (even if the test say so! It’s a troublesome setting)

Restart your server to load the changes:

service apache2 restart

Re-run the test, then:

• Ignore the open_basedir and upload_tmp_dir alerts, if any.
• You can enable some specific options with a .htaccess file

Change Apache 2 UID

Do not change the UID if you already have install web programs such as phpldapadmin or phpmyadmin, cacti, ...

Change the Apache UID

vim /etc/group

Change www-data UID

    www-data:x:10033:

Change the Apache GID

 
vim /etc/passwd

Change the group settings

	www-data:x:10033:10033:www-data:/var/www:/bin/false

Apply modifications

chown -R www-data:www-data /var/www/*
chown -R www-data:root /etc/php5/*

To take on the modifications you have to reboot your server.

Avoid DOS attacks

Source: Linux mag’ – Hors serie Apache2

You can protect your server from Denial Of Service (DOS) attacks through mod_evasive

apt-get install libapache2-mod-evasive

Prepare log directory

mkdir /var/log/apache2/mod_evasive
chown -R www-data:www-data  /var/log/apache2/mod_evasive

Enable module

a2enmod mod-evasive

Configuration

Create the configuration file

vim /etc/apache2/conf.d/mod_evasive.conf

Put:

# Mod evasive configuration
# Based upon Linux Mag 
<IfModule mod_evasive20.c>
	DOSHashTableSize 3097 

	# Limit user to 5 pages per 2 seconds
	DOSPageCount 5
	DOSPageInterval 2 

	# No more than 100 HTTP request per second (HTML, CSS, images, …) 
	DOSSiteCount 100
	DOSSiteInterval 1

	# Block client for 300 seconds
	DOSBlockingPeriod 300 
	# Send alert email
	#DOSEmailNotify "admin@myDomain" 

	# Log directory
	DOSLogDir "/var/log/apache2/mod_evasive" 

	# Command to execute on ban
	#DOSSystemCommand "/sbin/iptables -I INPUT -s %s -j DROP"

	# Ignore following IP and networks
	DOSWhiteList 127.0.0.1 
	#DOSWhitelist 66.249.65.*
<IfModule mod_evasive20.c>

DosHashTableSize = Size of the hash table.

• The greater, the more memory is required but the faster it is! The value must be a prime number

Apply changes

service apache2 restart