What is Web Application Firewall (WAF) Software?

WAF software products are used to protect web applications and websites from threats or attacks. The firewall monitors traffic between users, applications, and other internet sources. They're effective in defending against cross-site forgery, cross-site scripting (XSS attacks), SQL injection, DDoS attacks, and many other kinds of attacks. These software solutions provide automatic defense and allow administrative control over rule sets and customization since some applications may have unique traffic trends, zero-day threats, or web application vulnerabilities. These tools also provide logging features to document and analyze attacks, incidents, and normal application behaviors. Companies with web applications should use WAF tools to ensure all weak spots in the application itself are filled. Without WAF, many threats may go undetected, and data leakage may occur. They have truly become an obligatory component of any business-critical web application containing sensitive information. Key Benefits of Web Application Firewall (WAF) Software Protection against web-based threats Historical documentation of incidents and events Elastic, scalable web application protection

Why Use Web Application Firewall (WAF) Software?

There are a variety of benefits associated with WAF tools and ways they can boost security of applications deployed online. Most of the reasoning behind WAF usage is the generally accepted belief that web-based threats should be a concern for all businesses. Therefore, all businesses deploying web-based applications should be sure they are doing all they can to defend against the myriad cyberthreats that exist today. Some of the numerous threats WAF products can help defend against include: Cross-Site Scripting (XSS) — Cross-site scripting (XSS) is an attack where a malicious script is injected into websites using a web application to send malicious code. Malicious scripts can be used to access information such as cookies, session tokens, and other sensitive data collected by web browsers. Injection Flaws — Injection flaws are vulnerabilities which allow attackers to send code through an application to another system. The most common type is a SQL injection. In this scenario, an attacker finds a point in which the web application passes through a database, executes their code, and can begin querying whatever information they want. Malicious File Execution — Malicious file execution is accomplished when an attacker is able to input malicious files that are uploaded to the web server or application server. These files can be executed upon upload and completely compromise an application server. Insecure Direct Object Reference — Insecure direct object reference occurs when user input can directly access an application's internal components. These vulnerabilities can allow attackers to bypass security protocols and access resources, files, and data directly. Cross-Site Request Forgery (CSRF) — CSRF attacks force users to execute actions on a web application the user has permission to access. These actions can force users to unwillingly submit requests that may damage the web application or change their credentials to something the attacker can reuse to gain access to an application at a future date. Information Leakage — Information leakage can occur when unauthorized parties are able to access databases or visit URLs that are not linked from the site. Attackers may be capable of accessing sensitive files such as password backups or unpublished documents. Improper Error Handling — Error handling refers to preprogrammed measures that allow applications to dismiss unexpected events without exposing sensitive information. Improper error handling leads to a number of various issues, including the release of data, vulnerability exposure, and application failure. Broken Authentication — Broken authentication is the result of improper credential management functions. If authentication measures fail to function, attackers can walk by security measures without the valid identification. This can lead to attackers gaining direct access to entire networks, servers, and applications. Session Management — Session management errors occur when attackers manipulate or capture the tokenized ID provided to authenticated visitors. Attackers can impersonate generic users or target privileged users to gain access control and hijack an application. Insecure Cryptographic Storage — Cryptographic storage is used to authenticate and protect communications online. Attackers may identify and obtain unencrypted or poorly encrypted resources that may contain sensitive information. Proper encryption typically protects against this, but poor key storage, weak algorithms, and flawed key generation may put sensitive data at risk. Insecure Communications — Insecure communications occur when messages exchanged between clients and servers becomes visible. Poor network firewalls and network security policies can lead to easy access for attackers by gaining access to a local network or carrier device or installing malware on a device. Once applications are exploited, individual user information and other sensitive data becomes extremely vulnerable. Failure to Restrict URL Access — Applications may fail to restrict URL access to unauthorized parties who attempt to visit unlinked URLs or files without permission. Attackers may bypass security by directly accessing URLs containing sensitive information or data files. URL restriction can be accomplished by utilizing page tokens or encrypting URLs to restrict access unless they visit restricted pages through approved navigational paths.

Who Uses Web Application Firewall (WAF) Software?

The actual individuals using application firewalls are software developers and security professionals. The developer will typically build and implement the firewall, while it is maintained and monitored by security operations teams. Still, there are a few industries that may be more inclined to use WAF tools for various purposes. Internet Businesses — Internet businesses are a natural fit for WAF tools. They often have one or multiple public-facing web applications and various internal web apps for employee use. Both of these kinds of applications should be guarded by some kind of firewall, as well as additional layers of security. While nearly all modern businesses use web applications in some capacity, internet-centric businesses are more susceptible to attacks simply because they likely possess more web apps. E-Commerce Professionals — E-commerce professionals and e-commerce businesses that build their own online tools should be using WAF technology. Many e-commerce applications are managed by some kind of SaaS provider, but custom-built tools are incredibly vulnerable without an application firewall. E-commerce businesses who fail to protect their applications put the data of their visitors, customers, and business on the line. Compliant-Required Industries — Industries that require a higher level of compliance for data security should use a web application firewall for any application that communicates with a server or network with access to sensitive information. The most common business types with increased compliance requirements include health care, insurance, and energy industries. But many countries and localities have expanded IT compliance requirements across industries to prevent data breaches and the release of sensitive information.

Page 2 | Best Web Application Firewalls (WAF): User Reviews from August 2026

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Fortinet Managed Rules for AWS WAF

Fortinet’s WAF rulesets are additional security signatures that can be used to enhance the protections included in the base AWS WAF product. They are updated on a regular basis to include the latest threat intelligence from the award-winning FortiGuard Labs. The Complete OWASP Top 10 Ruleset provides a comprehensive package for web application protection offered by Fortinet to help address the OWASP Top 10 web application threats. Includes protection for various Injection attacks such as SQL and command Injection , Cross Site Scripting, General and Known Exploits, Malicious Bots and Common Vulnerabilities and Exposures (CVE).

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Link11

Link11 is a specialized European IT security provider headquartered in Germany, offering a comprehensive suite of cloud-native IT security services designed to help organizations prevent business disruptions and enhance their cyber resilience. With a global presence that spans Europe, North America, and Asia, Link11 focuses on safeguarding networks and critical applications against a wide array of evolving cyber threats. Targeted primarily at businesses that require robust security measures to protect their digital assets, Link11's services are particularly beneficial for sectors that are vulnerable to cyberattacks, including : - Finance - Healthcare - E-commerce. The company’s integrated security solutions cater to various use cases, from defending against Distributed Denial of Service (DDoS) attacks to ensuring the integrity of web applications and APIs. By addressing the specific needs of its clients, Link11 empowers organizations to maintain operational continuity and secure sensitive information. The key features of Link11's offerings include advanced Network Security, which utilizes machine learning to provide rapid DDoS protection. This capability enables: - Zero-time-to-mitigate defense against known attack vectors - Mitigation of new threats in under 10 seconds Additionally, the Web Application & API Protection (WAAP) platform combines essential security tools, including: - Web Application Firewall (WAF) - Web DDoS Protection - Bot Management - API Security This all-in-one solution is designed to defend against the OWASP Top 10 vulnerabilities and complex Layer 7 attacks, ensuring comprehensive protection for web applications. Moreover, Link11 enhances application performance through its Secure CDN and Secure DNS solutions, which leverage a global Anycast network to deliver maximum availability and speed. This focus on performance ensures that security measures do not compromise user experience, allowing businesses to operate efficiently while maintaining high levels of protection. Link11 is recognized as a BSI-qualified provider for DDoS protection of critical infrastructure (KRITIS) and adheres to stringent data security and compliance standards. The company holds certifications such as: - PCI-DSS - C5 - ISO 27001 The company’s high-performance, multi-terabit global network is continuously monitored by the Link11 Security Operations Center (SOC), providing immediate response capabilities and ongoing protection for a diverse range of industries worldwide. This commitment to security and operational excellence positions Link11 as a reliable partner for organizations seeking to enhance their cybersecurity posture.

Average Rating: 4.7/5.0

Total Reviews: 38

How Do G2 Users Rate Link11?

Has the product been a good partner in doing business?: 9.4/10 (Category avg: 8.7/10)
Traffic Controls: 9.5/10 (Category avg: 9.1/10)
Security Monitoring: 9.5/10 (Category avg: 9.0/10)
Issue Tracking: 9.0/10 (Category avg: 8.7/10)

Who Is the Company Behind Link11?

Seller: Link11
Company Website:
HQ Location: Frankfurt, DE
Twitter: @Link11GmbH
1,031 Twitter followers
LinkedIn® Page: www.linkedin.com
111 employees on LinkedIn®

Who Uses This Product?

Top Industries: Computer Software, Information Technology and Services
Company Size: 43% Medium, 30% Small

What Do G2 Reviewers Say About Link11?

AI-generated summary from verified user reviews

Pros

Users commend Link11 for its exceptional customer support, highlighting the team's responsiveness and technical expertise.
Users value the comprehensive API protection of Link11, praising the exceptional support and advanced security solutions.
Users praise Link11 for its superior DDoS protection, ensuring consistent security and uninterrupted service for mission-critical applications.
Users appreciate the ease of use of Link11, enabling quick implementation and efficient issue analysis.
Users value the premium support and advanced security features of Link11, enhancing web application protection and performance.

Cons

Users find complex rule management challenging, particularly for non-trained or junior employees when creating custom rules.
Users find the difficult learning curve of Link11 challenging, particularly for non-trained or junior staff creating custom rules.
Users find creating custom rules challenging, particularly for those who are non-trained or junior employees.

What Are Recent G2 Reviews of Link11?

"Outstanding DDoS Protection and Unmatched Reliability"

Rating: 5.0/5.0 stars

— Ben K.

Best Web Application Firewalls (WAF) - Page 2

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