Best Web Application Firewall (WAF) Solutions

A WAF works by preventing unauthorized data from leaving the app by adhering to a set of policies that help determine what traffic is malicious and what traffic is safe. A WAF acts as a transparent reverse proxy, or an intermediary that protects the web app server from a potentially malicious client. The proxy ensures that all traffic passes through it and separately sends filtered traffic to the application, hiding the IP address of the application service. In order to work properly, many WAFs require you to update their policies regularly to address new vulnerabilities. The policies tell the firewall what needs to be done if vulnerabilities or misconfigurations are found. Some WAFs, however, use machine learning to enable policy updates automatically.

• A standard firewall provides a barrier between external and internal network traffic. In contrast, a WAF protects web applications by targeting (HTTP) traffic.
  
• A network firewall protects a secure LAN network from a less secured or unsecured network whereas a WAF filters traffic that enters through the application layer.

• A network firewall is placed on the perimeter of the LAN network, acting as a barrier and controlling access to the LAN network by blocking illegitimate HTTP and HTTPS traffic from entering. In contrast, a WAF is placed close to the internet-facing applications.

• A network firewall is run on a dedicated hardware appliance, and watches the network layer by blocking unauthorized access from less secure zones. A WAF is different because it is extremely adaptable and can be run on a dedicated hardware appliance, through a virtual machine, or deployed as SaaS in the cloud.

Yes, a web application needs a firewall. WAF solutions protect businesses from web-based attacks targeted at applications. Without an application firewall, hackers can easily infiltrate the broader network through web application vulnerabilities. A WAF offers critical protection for any online business that needs to securely handle private customer data.

There are three different types of WAFs:

1. Hardware-based WAF: A hardware-based WAF is deployed through a hardware appliance, installed within the LAN close to the web and application servers. Hardware-based WAFs have fast speed and high performance. Due to their physical proximity to the server, they track and filter data packets to and from the website with very low latency. They are most suitable for large businesses.

2. Software-based WAF: Different from a hardware-based WAF, a software-based WAF is installed in a virtual machine instead of a physical hardware appliance. All the WAF components are essentially the same as a hardware WAF. The one difference is that users would need to have their own hypervisor to run the virtual machine. The biggest benefit of a software-based WAF is its flexibility. It can be used within an on-premises system, and can also be deployed in the cloud, connecting to cloud-based web and application servers. It is not as fast as a hardware-based WAF, since a higher latency is experienced during the monitoring and filtering process. Software-based WAFs are suitable for small and medium-sized organizations.

3. Cloud-based WAF: A cloud-based WAF is provided and managed directly by a service provider in the form of a SaaS. With a cloud-based WAF, the WAF components are entirely located in the cloud, so that the user does not need to install anything locally or in any virtual machines. Because these WAFs are cloud-based, they are very simple. The user does not need to install any software physically and only needs to enroll in a subscription plan. The user is not required to manage the WAF by themselves because the service provider is responsible for providing all the optimization and updates. However, the disadvantage is that there is not much room for customization, since the WAF is managed entirely by the service provider,

A WAF is usually placed close to the internet-facing applications. In most application architectures, a WAF is typically positioned behind the load-balancing tier to maximize utilization, reliability, performance, and visibility.

Without properly securing web applications, organizations face a very high risk of leaking their data. Attackers can always exploit the vulnerabilities of an application to gain access to the database, after which they could view, change, delete, and even exfiltrate data. If you do not have a WAF in place, data breaches are more likely to occur, which could potentially lead to the deterioration of customer trust, reputation, brand value, and share value, as well as direct financial loss due to heavy fines. In addition, a WAF is necessary because it helps meet compliance requirements, apart from also providing data encryption and multi-factor authentication.

When choosing a WAF, look for the following:

• Deployment options: Choose a WAF that offers different deployment options. An in-line WAF can be used to stop a live attack. On the flip side, in-line WAFs can slow traffic, and they are also more likely to block legitimate traffic. The other option is a passive WAF, also known as a tap/span WAF, which is placed outside the path and monitors traffic from a tap/span port. These types of WAFs cannot block attacks, but they can be set up to communicate with other systems that can be used to block traffic, such as the network firewall. You may also want a WAF that protects servers both on site and in the cloud. For this, a cloud-based WAF, or a WAF that allows you to use an API to monitor VM traffic, would be the better choice.

• Availability: It is important to take latency into account, especially if high availability is critical for your website and applications. It will also be essential that the WAF you choose does not become a single point of failure. You need to consider whether multiple WAF nodes can be configured, how many are possible, etc.

• Detection techniques: Most WAFs employ a combination of detection techniques. Choosing a WAF with more options is better. Some WAFs are also capable of behavioral analysis. With this type of WAF, suspicious traffic can be detected regardless of rules and signature updates. When evaluating WAFs, make sure to ask vendors for proof of false positives to negative rates as well as third-party test results to give you a better understanding of how successful the WAF’s detection features will be.

Of the many benefits that a WAF offers, here are the biggest advantages:

• WAFs prevent attacks, including SQL injections, cross-site scripting (XSS) attacks, and distributed denial of service (DDoS) attacks.

• WAFs stop customer data from being compromised.

• They ensure compliance with regulations like HIPAA and PCI.

• They free up your team’s resources by automatically running security tests and monitoring traffic.