A web application firewall (WAF) is a firewall that monitors, filters, and blocks data packets as they travel to and from a website or web application, A WAF can be either network-based, host-based, or cloud-based and is often deployed through a reverse proxy and placed in front of one or more websites or applications. Running as a network appliance, server plugin, or cloud service, the WAF inspects each packet and uses a rule base to analyze Layer 7 web application logic and filter out potentially harmful traffic that can facilitate web exploits.
The work of WAF is a common security control that is being used by enterprises to protect the system against all the malware infections, known and unknown threats along vulnerabilities. Through customized inspections, a WAF is able to detect and immediately prevent several of the most dangerous web application security flaws, which traditional network firewalls and other intrusion detection systems (IDSes) and intrusion prevention systems (IPSes) may not be capable of doing. WAFs are especially useful to companies that provide products or services over the Internet such as e-commerce shopping, online banking, and other interactions between customers or business partners.
How does it work?
A WAF analyzes Hypertext Transfer Protocol (HTTP) requests and applies a set of rules that define what parts of that conversation are benign and what parts are malicious. The main parts of HTTP conversations that a WAF analyzes are GET and POST requests. GET requests are used to retrieve data from the server, and POST requests are used to send data to a server to change its state.
A WAF can take two approaches to analyze and filter the content contained in these HTTP requests or a hybrid combination of the two:
- Whitelisting: A whitelisting approach means that the WAF will deny all requests by default and allow only requests that are known to be trusted. It provides a list of what IP addresses are known to be safe. Whitelisting is less resource-intensive than blacklisting. The downside of a whitelisting approach is that it may unintentionally block benign traffic. While it casts a wide net and can be efficient, it may also be imprecise.
- Blacklisting: A blacklisting approach defaults to letting packets through and uses preset signatures to block malicious web traffic and protect vulnerabilities of websites or web applications. It is a list of rules that indicate malicious packets. Blacklisting is more appropriate for public websites and web applications since they receive a lot of traffic from unfamiliar IP addresses that aren’t known to be either malicious or benign. The downside of a blacklisting approach is that it is more resource-intensive; it requires more information to filter packets based on specific characteristics, as opposed to defaulting to trusted IP addresses.
- Hybrid security: A hybrid security model uses elements of both blacklisting and whitelisting.
Types of web application firewalls
Network-based WAFs are usually hardware-based and can reduce latency because they are installed locally on-premises via a dedicated appliance, as close to the application as possible. Most major network-based WAF vendors enable replication of rules and settings across multiple appliances, thereby making large-scale deployment, configuration, and management possible. The biggest drawback for this type of WAF product is cost — there is an upfront capital expenditure, as well as ongoing operational costs for maintenance.
Host-based WAFs may be fully integrated into the application code itself. The benefits of a host-based WAF implementation include lower cost and increased customization options. Host-based WAFs can be a challenge to manage because they require application libraries and depend upon local server resources to run effectively. Therefore, more staff resources, including that of developers, system analysts, and DevOps/DevSecOps, may be required.
Cloud-hosted WAFs offer a low-cost solution for organizations that want a turnkey product that requires minimal resources for implementation and management. Cloud WAFs are easy to deploy, are available on a subscription basis, and often require only a simple domain name system (DNS) or proxy change to redirect application traffic. Although it can be challenging to place responsibility for filtering an organization’s web application traffic with a third-party provider, the strategy enables applications to be protected across a broad spectrum of hosting locations and use similar policies to protect against application-layer attacks. Additionally, these third parties have the latest threat intelligence and can help identify and block the latest application security threats.
Advantages of WAF Services
Now let us proceed further and have a check on some of the advantages of the services as those are mentioned below.
- Cross-site scripting (XSS)
- Structured Query Language (SQL) injection
- Web session hacking
- Distributed denial-of-service (DDoS) attacks
A WAF is important to the growing number of enterprises that provide products over the internet — including online bankers, social media platform providers, and mobile application developers — because it helps prevent data leakage. A lot of sensitive data, such as credit card data and customer records, is stored in back-end databases that are accessible through web applications. Attackers frequently target these applications to gain access to the associated data.
Banks, for instance, might use a WAF to help them meet the Payment Card Industry Data Security Standard (PCI DSS), which is a set of policies to ensure that cardholder data (CHD) is protected. Installing a firewall is one of the 12 requirements of PCI DSS compliance. This compliance applies to any enterprise that handles CHD. Since many newer companies employ mobile applications and the growing internet of things (IoT), an increasing number of transactions take place at the application layer using the web. For this reason, a WAF is an important part of a modern business’s security model.
While a WAF is important, it is most effective in conjunction with other security components, including IPSes, IDSes, and classic or next-generation firewalls (NGFWs). A comprehensive enterprise security model would ideally position a WAF alongside other firewall types, such as NGFWs, and security components, such as IPSes and IDSes, which are often included in NGFWs.
In reading this article it is very much clear that what does WAF services means. To know more about the service or to connect with us, you can send us an email or can contact us over the phone and we will be at your service.