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What is an application firewall

Nowadays, websites have become vital to the growth of a business. On account of websites, the company embraces a much larger audience and remains available to it continuously. However, websites are the regular target of cyber attacks against which companies must beware. Several security tools exist, including SSL certificates and the firewall application.

A firewall is a tool used to protect a network, a server or a machine. It execute this purpose by examining the data transferred to that network or machine and blocking unauthorized traffic. The application firewall or Web application firewall (WAF) is a type of firewall. It is intended for the protection of web applications including websites. Indeed, traditional firewalls, for network security in particular, are ineffective against attacks targeting websites.

How does it work?

The firewall can be software, hardware, or a combination of the two. But, in the particular case of websites, this is usually a software solution like ModSecurity. It is located between the web server and the Internet. Before HTTP / HTTPS requests reach the server, the application firewall examines them and determines whether they are legitimate or not. To do this, it is based on predefined filtering rules.

There are two security models for the application firewall. The first is the negative model which is easier to set up. In this case, the WAF takes action upon detection of a known attack. The second model, more efficient but complex to set up is the positive model. It is based on the analysis of the normal functioning of the web application. Thus, only the flow of information considered normal will be able to pass, it will block the rest. You can also configure the two models to work simultaneously to increase the efficiency of the firewall.

For logging problems, the firewall can be positioned in probe or cutoff mode. In probe mode, it detects and issues alarms in the event of an intrusion. Cutoff mode allows session tracking, authentication and authorization, and other benefits.

Why use an application firewall

Unfortunately many websites fall victim to cyber attacks due to ignorance of the importance of web security. Every day, the websites are subject to various attacks with more or less serious consequences. It is therefore important when looking for a web hosting plan to favor a web host for whom web security is a priority.

  • The application firewall can act as a shield against recently identified vulnerabilities on a website. It thus gives the webmaster time to be able to correct them.
  • WAF protects against SQL injections. This protects against theft of more or less important information stored in databases.
  • WAF protects a website against DDOS (Distributed Denial of Service) attacks. It is a very common cyber attack. Thousands of machines distributed around the world and controlled by master software, send simultaneous requests to a single host. This host becomes overloaded and may even stop functioning.
  • It also protects against HTTP session theft. Through this attack, the hacker impersonates a legitimate user. One can very well imagine the damage caused by this usurpation.
  • It also detects bots and worms by checking if a legitimate browser has issued a request.