Tag: Firewall

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How To Install Mod_Security Apache on CentOS 7

Install Mod_Security Apache on CentOS 7

ModSecurity is an open source, cross platform web application firewall (WAF) developed by Trustwave’s SpiderLabs. It has a robust event-based programming language which provides protection from a range of attacks against web applications and allows for HTTP traffic monitoring, logging and real-time analysis. In this tutorial we will learn how To Install Mod_Security Apache on CentOS 7

This article assumes you have at least basic knowledge of Linux, know how to use the shell, and most importantly, you host your site on your own VPS. The installation is quite simple and assumes you are running in the root account, if not you may need to add ‘sudo’ to the commands to get root privileges. I will show you through the step by step installation ModSecurity on a CentOS 7 server.

Install Mod_Security Apache on CentOS 7

Step 1. First, let’s start by ensuring your system is up-to-date.

yum clean all
yum -y update

Step 2. Installing Mod_Security Apache on CentOS

Install Dependencies for mod_security:

yum install gcc make httpd-devel libxml2 pcre-devel libxml2-devel curl-devel git

Next, download latest stable release of mod_security source code from their official website to your server:

wget https://www.modsecurity.org/tarball/2.9.3/modsecurity-2.9.3.tar.gz
tar xzf modsecurity-apache_2.9.3.tar.gz
cd modsecurity-apache_2.9.3
./configure
make install
cp modsecurity.conf-recommended /etc/httpd/conf.d/modsecurity.conf
cp unicode.mapping /etc/httpd/conf.d/

Step 3. Configuring Mod_Security.

# nano /etc/httpd/conf/httpd.conf
LoadModule security2_module modules/mod_security2.so

Now set the basic rule set in your httpd.conf file. Add the following lines of code at the end of the file:

<IfModule security2_module>
    Include conf.d/modsecurity.conf
</IfModule>

Save the changes and restart Apache:

systemctl restart httpd

Step 4. Download and configure OWASP (Open Web Application Security Project) core rule set for a base configuration.

cd /etc/httpd
git clone https://github.com/SpiderLabs/owasp-modsecurity-crs.git
mv owasp-modsecurity-crs modsecurity-crs
cd modsecurity-crs
cp modsecurity_crs_10_setup.conf.example modsecurity_crs_10_config.conf

Open the Apache configuration file again, and add the following lines at the end of the file:

# nano /etc/httpd/conf/httpd.conf

Include modsecurity-crs/modsecurity_crs_10_config.conf
Include modsecurity-crs/base_rules/*.conf

Next, restart the Apache service to enable mod_security module:

systemctl restart httpd

Congratulation’s! You have successfully installed Mod_Security. Thanks for using this tutorial for installing Mod_Security on CentOS 7 system. For additional help or useful information, we recommend you to check the official ModSecurity website.

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How To Configuration Iptables Firewall on CentOS

Configuration Iptables Firewall on CentOS

Iptables is a user space application program that allows a system administrator to configure the tables provided by the Linux kernel firewall (implemented as different Netfilter modules) and the chains and rules it stores. Different kernel modules and programs are currently used for different protocols; iptables applies to IPv4, ip6tables to IPv6, arptables to ARP, and ebtables for Ethernet frames. (Read more on: wikipedia)

Configuration Iptables Firewall on CentOS

Setting up iptables

You can use the following procedure to verify that iptables has been installed and view the status of iptables. Open terminal and type the following command:

# iptables -V
# yum info iptables

iptables-centos

If the above message does not appear, you can type the following command to install iptables:

 # yum -y install iptables

Understanding Firewall, At present here are total four chains:

  • INPUT : The default chain is used for packets addressed to the system.
  • OUTPUT : The default chain generating from system.
  • FORWARD : The default chains is used when packets send through another interface.
  • RH-Firewall-1-INPUT : The user-defined custom chain.

Target Meanings

  • The target ACCEPT means allow packet.
  • The target REJECT means to drop the packet and send an error message to remote host.
  • The target DROP means drop the packet and do not send an error message to remote host or sending host.

The default iptables configuration on CentOS does not allow access to the HTTP (TCP PORT # 80) and HTTPS (TCP PORT # 443) ports used by Nginx web server. You can do step by step to configure:

Step 1: Flush all iptables rules

# iptables -F
# iptables -X
# iptables -t nat -F
# iptables -t nat -X
# iptables -t mangle -F
# iptables -t mangle -X

Step 2: Set default rules

# iptables -P INPUT DROP
# iptables -P FORWARD ACCEPT
# iptables -P OUTPUT ACCEPT

Step 3: Allow access to HTTP (port 80) and HTTPS (port 443)

# iptables -A INPUT -i lo -j ACCEPT 
# iptables -A INPUT -m state --state ESTABLISHED -j ACCEPT 
# iptables -A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT 
# iptables -A INPUT -p icmp -j ACCEPT
# iptables -A INPUT -m state --state NEW -m tcp -p tcp --dport 80 -j ACCEPT
# iptables -A INPUT -m state --state NEW -m tcp -p tcp --dport 443 -j ACCEPT

 Turn on and save iptables

Type the following two commands to turn on firewall:

# chkconfig iptables on
# service iptables save