What is WAF?

WAF abbreviated as Web Application Firewall is meant to filter healthy application traffic, watch out for the weakest points, and discover vulnerabilities. It inspects inbound and outbound application HTTP traffics to prevent common attacks, which arise from code vulnerabilities like SQL Injection, file inclusion, cross-site scripting (XSS), and cross-site forgery.

WAF automatically blocks attackers from finding these security vulnerabilities, offering an adequate time to patch up all loopholes. It precisely monitors the web application traffic and services as a protocol layer 7 defense. It can also be used as a tool for load balancing as well as keep-live optimization.

Types of Web Application Firewall

Network-based firewalls

Protects computer networks from attacks by filtering traffic going in and out of the network


Host-based firewalls

Monitors application systems call and protect the host it is operating on


Open source WAF

The free WAF detects application-level threats and secure web apps at no charge


Cloud-based WAF

Provided as a SaaS, the WAF protects cloud-hosted web applications by leveraging the power of massive network edge.


How does a WAF work?

Web Application Firewall sits between the web services and the clients. The requests from clients are routed through the WAF where monitors take place for questionable behavior. It checks the header and contents of the requests. By enforcing a set of pre-defined rules, WAF filters what parts of the communication are malicious and what parts are benign. The WAF policies can be customized according to the risk and security needs specific to your applications. Fake traffics, are immediately blocked, and further tested to prevent harmful bots from proceeding.

With smart web application provider who will structure WAF into a comprehensive security package, you can keep security threats bay.


A WAF can be configured in two ways:

Whitelist Model or Positive Security Model

This WAF allows only approved traffic to access the web application. In this configuration, only a limited number of users are allowed while blocking other traffics.

Blacklist Model or Negative Security Model

This block first approach operates against common security models by blocking specific malicious actors, vulnerabilities, and attack signals.

The most recommended method is configuring a hybrid model, which functions in both the whitelist and blacklist model and
offers the benefits of both approaches of the WAF.

Why Most of The Business need WAF?

These days, businesses overwhelmingly develop and buy web applications. The web apps spread throughout an enterprise and are increasingly accessed by both internal and external users, related defenses are required beyond the network perimeter.

Online financial services, eCommerce websites, or any other kind of services involving interactions with business partners and customers is at a high risk of security attacks. In these cases, Web Application Firewalls can help prevent data thefts and fraud. As WAF are not built to defend from all kinds of attacks, it functions as part of an array of security tools, which backs a comprehensive web application security program.

Another important benefit of WAF is obtaining protection against zero-day attacks: newborn malware, which is not identified by any behavior analysis – the most dangerous type of security threat, that traditional firewalls aren’t equipped to prevent or mitigate.

WAF are unique in their capabilities like:

  • Validate code inputs, thereby stops XSS, SQL injection , and directory traversal attacks
  • Spot session, cookie, or parameter tampering attacks
  • Block attacks, which exploit a weakness in custom web properties
  • Inspect SSL-encrypted traffic to detect all kinds of embedded threats
  • Avert threats, which execute by exploiting logic loopholes
  • Enables compliance with the need for PCI DSS
  • Protect against DDoS attacks

Underpinning all these protections, market-leading WAF like Indusface’s AppTrana also ensures support for a signature-based component and network-layer access control models for detecting known security threats.

Key Criteria for Choosing Enterprise WAF

The WAF market is still undetermined, with several unrelated products falling under the umbrella of a Web Application Firewall. Several products offer functionality above and beyond what one would figure as a WAF.
Here are the key criteria for choosing appropriate WAF for your applications:


Protection against application-layer attacks

A good WAF should ensure application security by providing comprehensive attack protection from OWASP (Open Web Application Security Project) Top 10 security risks, SQL injection, DDoS attacks, XSS, fraudulent transaction, in-browser session hijacking, and zero-day exploits.


Automatic Attack Detection

A good WAF comes with automatic bot-detection capabilities to ensure always-on protection against web scraping, 7 DDoS attacks, and brute force attacks


Ease of Management

The strongest WAF solutions simplify the policy creation, minimize configuration errors, and ensure the effectiveness of each security policy. Make sure the WAF you choose should allow you use the services of the experts to update policies and manage it without false positives.


Behavioral Analysis

WAF can also analyze the volumetric traffic patterns and scan for abnormal behavior with a set of pre-defined rules. It assesses average transactions per second, server response time, and session, which request too much traffic to find whether an incident has commenced


High availability and Throughput

If you deploy a WAF in a high-traffic environment, it will be competent enough to process a certain amount of traffic without compromising speed.


Zero False Positives

WAF should never block any authorized request while stopping fraudulent traffic.


Logging and Reporting

It offers visibility to traffic and attack trends, acceleration of incident response, data aggregations for forensics, and recognition of unforeseen threats before exploits occur.


Advanced Bot Protection

It ensures seamless control over bot traffic and accurately distinguishes malicious bots from good bots to stop online fraud via competitive price scrapping and account takeover.


API Security

Automated API protection with API-specific DDoS/Bot mitigation policies and complete coverage over API risks shields your application and APIs from exploitation.

Top WAF (Web Application Firewall) Vendors

The surge in the demand for strict security standards and cloud-based solutions accelerates the growth of the WAF market, with a wide range of products providing various levels of security features. Choosing the right WAF product depends on your business requirements, budget, and priorities. Here is a list of the 10 most significant Web Application Firewalls that matters most.

  • AppTrana Fully Managed Web Application Firewall
  • Cloudflare WAF
  • Akamai WAF
  • Sucuri Website Firewall
  • Imperva WAF
  • Citrix WAF
  • Barracuda WAF
  • F5 Advanced WAF
  • Fortinet FortiWeb

Top 4 WAF Products Compared

Web Application Firewall Features Attacks Price Compare
Check for false positives, uncover weak spots, Managed Pen-testing, Fully Managed Custom-rules and takes ownership to optimize it with Zero False positive, DDoS & Bot Mitigation, Whole site Acceleration (CDN) OWASP Top 10, SQL Injection, Cross-site Scripting, Cookie poisoning, Parameter Tampering, SANS 25 Vulnerabilities, Zero Day Attacks and more Advance: $99 per month (30GB consumption per month included)
Premium: $399 per month (150GB consumption per month included)
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DDoS attack mitigation, DDoS Alerts Issue Tracking, Logging and Reporting, Application-Layer Control
Limits comment spam, SQL injections, DDoS attacks, Protects key ports OWASP Top 10 and more
Business plan with WAF: $200 per month. (if rate control is enabled no free consumptions in plan and additional bandwidth charge apply) Managed custom rules starts at more than a few thousand dollars per month AppTrana Vs CloudFlare
Advanced API Security, Customizable and Automated Protection, Granular Attack, Mitigation SLA,Managed Security Services
SQL injection, Advanced Application and Network Layer, DDoS attacks, XSS, Malicious file execution
Free Trials,
Quote based Plans and most of the deployment starts at more than a few thousand dollars per month per website
AppTrana Vs Akamai
Improved web traffic visibility, Easy Maintenance, web application protection, Agile protection against web attacks
DDoS Attacks, Cross-site Scripting, SQL Injection
Depends on number of rules, number of pages,number of request and can be anywhere from $20 - $300 per month or more AppTrana Vs AWS WAF