What is Web Application Firewall (WAF)?

Web Application Firewall (WAF) is a specialized security tool that acts as a protective shield for web applications. It works by filtering network traffic, examining each individual request to the server and checking whether it poses a potential threat. WAF protects applications against SQL injection attacks, cross-site scripting (XSS), DDoS attacks, and other threats that may lead to data leakage or damage to the application.

WAF is a specialized tool that allows you to secure a vulnerable application without interfering with it itself, which is very useful in situations when, for example, we are covered by a warranty contract and have to wait for a service technician or the software is no longer supported. The WAF acts as an intermediary between the client and the application server, and each request is first processed by the WAF, which checks whether it contains malicious code and whether it poses a threat to the application.

WAF is an essential tool for companies that want to protect their web applications against hacker attacks and other threats. Thanks to WAF, web applications are protected against attacks, which allows users to use them safely.

Web Application Firewall performs several basic functions that are designed to protect your web application from hacker attacks. Here are some of the most important WAF features:

WAF types

There are two main types of Web Application Firewall: application-level WAF and network-level WAF.

WAF works at the application layer and analyzes HTTP traffic between the application and the Internet. Thanks to this, WAF can block dangerous patterns that may indicate attack attempts.

The traffic analysis process

WAF analyzes network traffic to detect dangerous patterns. The traffic analysis process includes, among others: checking HTTP headers, form content, URL parameters and query header content. WAF compares this data with the security rules that were defined earlier.

WAF can block network traffic that does not meet certain security requirements. This may include blocking network traffic from a specific IP address or blocking network traffic containing unsafe patterns.

Threat detection methods

WAF uses various threat detection methods. One of the most popular methods is the use of security rules. Security rules are a set of instructions that specify what types of network traffic should be blocked.

Another popular method is the use of signatures. Signatures are patterns that correspond to signs specific to specific attacks. WAF compares network traffic with signatures to detect attacks.

WAF can also use heuristics to detect new types of attacks. Heuristics are a technique used to detect unknown threats. WAF analyzes network traffic to detect patterns that may indicate new types of attacks.

Protection against attacks

WAF acts as a shield to protect your web application from attacks such as Cross-site Scripting (XSS), SQL Injection and DDoS attacks. Because WAF blocks attacks at the application level, your application is more resistant to attacks, and you can rest easy knowing that your application is safe.

Compliance with regulations

WAF helps meet the requirements of various regulations, such as PCI-DSS and GDPR. Because WAF blocks SQL Injection and XSS attacks, your web application is less susceptible to data privacy violations, which allows you to meet the requirements of personal data protection regulations.

WAF is an extremely useful tool for anyone who wants to protect their web application against attacks. There are many benefits to using WAF, and since WAF is easy to use, you can secure your web application in no time.

Once you have decided to use WAF, you need to choose the right solution that will meet your requirements. Hardware, cloud and hybrid solutions are available on the market. Each of them has its advantages and disadvantages, so it is worth carefully analyzing which model will be best for you.

Hardware solutions

Hardware solutions are dedicated devices that are installed in the network. WAF acts as a network gateway and protects against attacks. Hardware WAF provides high performance and is able to handle heavy loads. This is a good solution for large companies that need protection against DDoS attacks.

Cloud solutions

Cloud solutions are WAFs available in the cloud. WAF runs as a service on the cloud provider's servers. This solution is easy to implement and configure. Cloud WAF offers flexibility and scalability because you can easily increase or decrease processing power depending on the needs of your business.

Hybrid solutions

Hybrid solutions are a combination of hardware and cloud solutions. Hybrid WAF provides high performance and flexibility. This solution is ideal for companies that need protection against DDoS attacks, but at the same time want the flexibility and scalability of a cloud solution.

Security policies

WAF security policies allow you to define what types of network traffic are allowed and what are blocked. You can define policies for different types of traffic, such as HTTP, HTTPS, or SQL traffic.

You can configure security policies in WAF to block SQL Injection attacks, Cross-Site Scripting (XSS), and much more. You can also add rules for specific IP addresses to block or allow access to your web application.

Monitoring and reporting

You can configure WAF to send email notifications or alerts to your event management system (SIEM) when threats are detected. You can also configure WAF to generate reports on detected threats and network traffic.

WAF also allows you to monitor the performance of your web application. You can monitor network traffic and application performance to identify performance issues and optimize your web application.

Web Application Firewall (WAF) is a tool that can be effectively integrated with other security systems. Integration with other tools allows for better protection of web applications against attacks.

One such tool is the intrusion detection system (IDS). The cooperation of WAF with IDS allows for more effective detection of attacks and blocking them before reaching the application. IDS can detect attack attempts based on network logs and then pass this information to the WAF, which blocks traffic from suspicious IP addresses.

Another tool that a WAF can be integrated with is an intrusion prevention system (IPS). WAF and IPS work in a similar way, but IPS works at the network level while WAF works at the application level. Integration of WAF with IPS allows for more effective protection against DoS attacks and attacks at the network level.

WAF can also be integrated with security monitoring systems that allow you to track network activity to detect suspicious behavior. By integrating with such systems, you can respond to attacks faster and avoid serious security problems.

False positives

One of the biggest challenges related to WAF is the emergence of the so-called false positives. This means that the WAF can block access to some elements of the website that are not actually dangerous. This is because WAF uses scanning algorithms that cannot always accurately determine whether an item is malicious or not.

This may lead to situations where users have difficulty accessing certain features of the website, which in turn may impact their user experience. To minimize the occurrence of such situations, it is worth regularly monitoring WAF operation and adapting its settings to the specifics of the website.

Performance management

Another challenge with WAF is performance management. WAF acts as an additional layer of protection that analyzes every HTTP request, which can lead to a decline in website performance.

To minimize the impact of WAF on website performance, it is worth using appropriate settings and optimizations. For larger sites, you may need to use more advanced solutions such as distributed WAF or load balancing.