Open Source WAF: The Best Web Application Firewall Solutions
The Internet is comparable to the Wild West. When a website goes live, it is immediately inundated with negativity from all angles. The vast majority of this traffic consists of bots (from robots, and automated programs that trawl the internet for vulnerable websites), which do not adhere to speed constraints.
When vulnerabilities are exploited by bots, this can lead to a website being defaced, data being stolen (usernames and passwords, sensitive private information, etc.), or even becoming a zombie bot among other zombie bots that go on to infect other vulnerable websites.
Botnets, with the computing power and internet bandwidth held captive by them, are eventually rented out to the highest bidder on the black market. There, vulnerabilities may inflict a variety of very real-world harms.
If you own an internet business, you must prevent hackers from destroying your website. If your website becomes infected with hacker code, search engines will not link to it. Protect your organization with a firewall for web applications.
So, on top of the regular security best practices to prevent bad things from happening, occasionally a WAF is implemented as a first line of protection.
A web application firewall (WAF) is a form of application firewall that provides visibility and analysis of HTTP(S) traffic to and from an online application. Its purpose is to thwart attacks designed to refuse service and steal data. It grants the administrator direct control over the requests and replies flowing through the system without requiring modification of the backend code. A WAF differs from a conventional firewall in that it protects a particular online application or group of web apps. And it does so without interacting with online apps.
There are several free WAFs to protect your web applications. The most delicate aspect of open-source WAF is the ability to customize the code based on your projects.
Through this article, the pros and cons of using open source WAF solutions, the best open source WAF solutions, must-have WAF solution features, and security concerns with open source WAF solutions will all be covered.
Figure 1. What is a Web Application Firewall (WAF)?
What are the Best Open Source WAFs?
The following open-source Web Application Firewall might be helpful if you are seeking a free alternative to commercial WAF to safeguard your website. Top Free and Open-source WAFs are as follows.
- NAXSI
- WebKnight
- Shadow Daemon
- Coraza
- OctopusWAF
- IronBee
- ModSecurity
- SafeLine
1. NAXSI
NAXSI is an acronym for Nginx Anti XSS and SQL Injection. Technically, it is a third-party Nginx module that is bundled with several UNIX-like systems. By default, this module reads a limited selection of basic (and understandable) rules encompassing 99 percent of known patterns associated with website vulnerabilities.
Naxsi has a basic ruleset and is expandable with user-defined rulesets. The configuration occurs in the context of Nginx. The WAF is adaptable to various contexts and web applications by virtue of scores for individual rules and configurable thresholds for blocking operations.
Naxsi may examine many data, including URLs, request parameters, cookies, headers, and the POST body, and it can be enabled or disabled at the location level in the Nginx configuration. Automatic whitelist generation simplifies upstream firewall deployment and eliminates any false positives. Other applications, such as NX-Utils and Doxi, simplify administration, report production, and ruleset modifications.
NX-utils, which are included with Naxsi, are highly useful for producing whitelists and reports. First, the NX-utils collection consists of intercept mode, which enables Naxsi to record requests stopped by the WAF for future reports and whitelists in a database, and report mode, which visualizes the saved events. A future version of NX-Utils will enable enhanced report processing and filtering in order to evaluate WAF events with greater precision.
NAXSI supports popular reliable server platforms, like NetBSD, FreeBSD, OpenBSD, Debian, and Ubuntu. You can easily utilize a WAF on OPNsense using NAXSI, which is a loadable module for the NGINX web server plugin. NAXSI has two sorts of rules.
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Main Rules: These rules apply internationally. Blocking code snippets that might be exploited to obtain unauthorized access to the server (such as SQL-/XPATH-injection for data access) or to take control of a foreign client (for example XSS).
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Basic Rules: These rules are typically used in places to whitelist primary rules by ID or for supplementary rules.
NAXSI, unlike the majority of Web Application Firewalls, does not rely on a signature database like an antivirus, and so cannot be bypassed by an "unknown" attack method. Naxsi means free software (as in freedom) and free to use.
NAXSI works as a DROP-by-default firewall. NAXSI only filters GET and PUT requests, and its default setup acts as a DROP-by-default firewall, thus you must add the ACCEPT rule for it to function properly.
What are the features of NAXSI?
The primary features of NAXSI are listed below.
- Minimum memory footprint and processing time
- Resistance against assaults with hazardous characteristics and expressions that are unknown.
- Easy to administer compared to other WAFs
- Effective learning procedure
NAXSI is best for choosing a WAF that's compatible with NGINX, in light of ModSecurity's EoL.
Figure 2. NAXSI
2. WebKnight
Given the rise in online dangers, protecting a web application is always a challenge. You should investigate every option for protecting your website from hackers. If you wish to secure an IIS-hosted website, you should consider using WebKnight WAF.
AQTRONiX's WebKnight is an open-source web application firewall for IIS web servers. It prevents harmful requests from reaching the IIS by scanning all requests.
All blocked requests are logged by default, and you may modify this to suit your needs. WebKnight 3.0 has an admin web interface for configuring rules and doing administrative chores, including statistics.
What are the features of WebKnight?
Some of the prominent features of WebKnight are given below.
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Interface for administration - handy for managing WebKnight and statistics
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Logging - log requests that are blocked or handled by WebKnight
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Use with WebDAV, Cold Fusion, OWA, Share Point, etc
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Using brute force against defenses
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Block IP that is handy for blocking incoming requests from known malicious IP addresses
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Hotlinking security
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Robots obstructing
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Examine both GET and POST payloads
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Run-time update - there is no need to restart IIS while updating WebKnight
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SSL session encryption
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SQLi, XSS, CSRF, and data loss prevention(DLP)
WebKnight is best for protection against SQL injection, directory traversal, character encoding, and buffer overflow.
Figure 3. WebKnight
What are the benefits of WebKnight?
Let's take a look at what benefits it has in addition to the features listed above. Here are some of the benefits of WebKnight.
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Protects your web application from threats and also stops malicious robots.
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Provides information about the ongoing attacks and increases the blue team's visibility.
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Achieve PCI DSS compliance requirements.
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Open source (GNU GPL) with just support fees.
3. Shadow Daemon
Shadow Daemon is a suite of tools designed to identify, record, and prevent web application attacks. The Shadow Daemon is technically a web application firewall that intercepts requests and removes harmful parameters. It is a modular solution that isolates online applications, analyses, and interfaces in order to boost security, flexibility, and scalability.
Shadow Daemon is a free application. It is offered under the GPLv2 license, meaning the source code can be studied, updated, and distributed by anybody.
The Shadow Daemon is simple to install and maintain using a well-organized web interface that enables in-depth analysis of threats.
The interface includes shell scripts for sending weekly reports via email, rotating logs, and similar tasks.
The Shadow Daemon can identify common attacks such as:
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SQL injections
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XML injections
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Code injections
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Command injections
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Cross-site scripting
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Local/remote file inclusions
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Backdoor access
Shadow Daemon is supported by in-depth documentation and a vibrant community. This is an easy-to-use and manageable open-source firewall for web applications.
The Shadow Daemon, unlike many other web application firewalls, does not entirely block malicious requests whenever feasible. Instead, it removes just the potentially harmful components of a request before allowing it to proceed. This prevents attacks while not needlessly frustrating visitors in the event of false positives.
Shadow Daemon is best for those who wish to host their own dynamic website without always worrying about vulnerabilities and attacks.
Shadow Daemon is best for those who wish to determine whether and how their website is under attack.
Shadow Daemon is best for those who do not wish to blindly rely on closed-source, expensive, and secretive software.
Figure 4. Shadow Daemon
What are the features of Shadow Daemon?
Some characteristics of Shadow Daemon are listed below.
- Combining blacklists and whitelists allows for accurate detection.
- Extensive coverage with numerous connectors
- Closer to the application for increased safety
- Only block harmful portions of malevolent requests
4. Coraza
Coraza is an open-source, enterprise-grade, high-performance Web Application Firewall (WAF) designed to safeguard your most cherished apps. It is developed in the Go programming language, supports ModSecurity and SecLang rule sets, and is fully compatible with the OWASP Core Rule Set.
Coraza is a drop-in replacement for the soon-to-be-discontinued Trustwave ModSecurity Engine, and it supports SecLang rule sets as an industry standard.
Coraza is one of the best WAFs since it is a community project with a clear continuous development roadmap.
Figure 5. Coraza
What are the features of Coraza?
The main features of Coraza are as follows.
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Security: Coraza utilizes the OWASP Core Rule Set (CRS) to defend your web applications from a broad variety of threats, including the OWASP Top Ten, with minimal false positives. CRS defends against a variety of typical attack types, including SQL Injection (SQLi), Cross Site Scripting (XSS), PHP & Java Code Injection, HTTPoxy, Shellshock, Scripting/Scanner/Bot Detection, and Metadata & Error Leakages.
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Extensible: At its heart, Coraza is a library with several connectors for deploying on-premise Web Application Firewall instances. Create your own audit loggers, persistence engines, operators, and actions to expand Coraza as much as you like.
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Performance: Coraza can manage large websites and tiny blogs with a minimum performance effect.
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Accessibility: Anyone may comprehend and alter the Coraza source code. It is simple to add additional features to Coraza.
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Community: Coraza is a community-driven endeavor; contributions are welcome and all suggestions are examined.
A Golang compiler v1.16+ is a prerequisite. Linux distribution (Debian or Centos recommended, Windows not supported yet) is available now.
5. OctopusWAF
OctopusWAF is an open-source Web application firewall written completely in C that makes numerous connections using libevent. The event-driven design is geared for many concurrent connections (keep-alive), which is essential for AJAX applications with high speed. This tool is quite lightweight. You may use it in any desired manner. This resource is ideal for securing particular endpoints that require customized security.
What are the features of OctopusWAF?
The main features of OctopusWAF are as follows.
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Reverse proxy capability
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Detect anomalies using regular expressions and lib PCRE resources
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Detect security anomalies using string-matching algorithms such as DFA, horspool, and karp-rabin
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Detect anomalies in security using libinjection
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Options for log saving
Octopus WAF is best for organizations of all sizes that need to protect their web applications from attacks. It is particularly well-suited for organizations that have a high-profile online presence or that handle sensitive data.
6. IronBee
At the 2011 RSA Conference, Qualys, Inc., the leading supplier of on-demand IT security risk and compliance management solutions, introduced IronBee, a new open source project that will deliver the next generation of web application firewall (WAF) technology.
Increasing web application usage and the shift to cloud computing require the deployment of WAF technology to secure data and comply with requirements such as payment card industry (PCI) compliance. With the release of IronBee, Qualys is establishing a community of commercial and open source contributors that will enable businesses of all sizes to adopt next-generation WAF technology to safeguard their data and IT assets.
IronBee is one of the best WAFs since it has a culture of contribution, enabling information sharing.
IronBee is best for businesses of all sizes who are looking to improve their customer service and sales efforts. Its features are designed to automate tasks, provide 24/7 support, and personalize the customer experience.
What are the features of IronBee?
The main features of IronBee are listed below.
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Highly portable and exceptionally light
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Modern application security assessment engine that offers new processing capabilities and HTTP traffic analysis.
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Apache Software License v2 is a non-viral open source license that permits participation from both people and commercial enterprises, thus building a community of both users and creators.
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Built from the ground up for numerous deployment options, including passive, embedded, out-of-process, and reverse proxy.
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Modular architecture enables contributors to simply build their own modules without having a thorough grasp of the IronBee architecture, as well as facilitates the packaging of configuration information and modules based on user requirements.
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Community-based effort to collect, consolidate, and distribute the information required to defend web applications.
Figure 6. IronBee
7. ModSecurity
ModSecurity sometimes referred to as Modsec, is an open-source web application firewall (WAF). Originating as a module for the Apache HTTP Server, it has grown to include a variety of Hypertext Transfer Protocol request and response filtering capabilities as well as other security features across several platforms, including Apache HTTP Server, Microsoft IIS, and Nginx. It is a popular choice for both on-premise and cloud-based deployments. It is free software distributed under the Apache 2.0 license.
Effective July 1, 2024, Trustwave will no longer provide support for ModSecurity. The maintenance of the ModSecurity code will thereafter be returned to the open-source community.
The NGINX ModSecurity WAF is a web application firewall (WAF) based on ModSecurity 3.0, a rewrite of the original ModSecurity software that functions as a native dynamic module for NGINX Plus. The NGINX ModSecurity WAF may be used to prevent a wide variety of Layer 7 attacks and adapt to new threats with virtual patching. Despite having a free version, NGINX ModSecurity is not an open-source project, so keep that in mind.
ModSecurity's open-source community is active and regularly releases updates. The complimentary regulations provided by ModSecurity are sufficient to enhance the security of the web application. ModSecurity lacks a graphical user interface, so you should consider WAF-FLE if you require one. It allows the event to be stored, searched, and viewed in a console.
What are the features of ModSecurity?
The main features of ModSecurity are as follows.
- Complete HTTP traffic logs
- Real-time application security monitoring and access control
- Web application fortification
- Continual passive security evaluation
- Extensive documentation
NGINX ModSecurity WAF is best for preventing common vulnerabilities like SQL Injection and XSS.
Figure 7. NGINX ModSecurity
8. SafeLine
SafeLine is a Web Application Firewall (WAF) powered by sophisticated semantic analysis algorithms and is well regarded in professional domains. It is a self-hosted Web Application Firewall (WAF) designed to safeguard your web applications against cyber attacks and vulnerabilities. The community edition of SafeLine is a streamlined variant of the business product, intended to be more accessible and complimentary for community use.
SafeLine safeguards web applications against threats like SQL injection, XSS, code injection, OS command injection, CRLF injection, LDAP injection, XPath injection, RCE, XXE, SSRF, path traversal, backdoor access, brute force assaults, HTTP flood, and bot abuse, among others.
SafeLine is highly endorsed among all Web Application Firewalls (WAFs). The Community Edition utilizes the security features of the business edition, guaranteeing protection. The SafeLine Community Edition gained significant popularity on GitHub immediately after its debut for this primary reason.
Figure 8. SafeLine
The primary characteristics of SafeLine are as follows.
- Dynamic Protection: When dynamic protection is on, HTML and JavaScript code on your web server will be encrypted dynamically with each visit.
- Prevent Web Attacks: It provides protection against several online attacks, including SQL injection, XSS, code injection, OS command injection, CRLF injection, XXE, SSRF, path traversal, and others.
- Authentication Challenge: When the authentication challenge is activated, visitors must input the password; otherwise, they will be denied access.
- Anti-Bot Challenge: Implement anti-bot challenges to safeguard your website from bot assaults, permitting human users but obstructing crawlers and bots.
- Rate Limitation: Protect your web applications against DoS assaults, brute force efforts, traffic spikes, and many forms of abuse by using traffic throttling for instances that above established thresholds.
What is a Web Application Firewall (WAF)?
A web application firewall, or WAF, is a security tool that monitors, filters, and blocks incoming and outgoing data packets from a web application or website. The purpose of a web application firewall (WAF) is to defend web applications from frequent web attacks. Through the screening and monitoring of HTTP traffic between a web application and the Internet, a web application firewall, or WAF, contributes to the protection of web applications. WAF defends web applications against threats like SQL injection, file inclusion, cross-site scripting (XSS), and cross-site forgery.
Businesses frequently employ web application firewalls as a security measure to guard against known and undiscovered threats and vulnerabilities, such as malware infections, impersonation, and zero-day exploits.
According to the OSI model, a WAF is a protocol layer 7 protection and isn't made to fight against every kind of assault. This attack mitigation technique is typically a component of a toolkit that, when combined, provides a comprehensive defense against a variety of attack vectors.
To provide a barrier between a web application and the Internet, a WAF might be placed in front of it. A WAF is a sort of reverse proxy that shields the server from exposure by requiring clients to pass through it before contacting the server, whereas a proxy server uses an intermediate to conceal the identity of a client computer.
A WAF functions according to a set of guidelines, sometimes referred to as policies. By removing harmful traffic, these policies seek to defend against application vulnerabilities. A WAF's usefulness stems in part from how quickly and easily policy changes can be made, enabling a quicker reaction to different attack vectors. For example, rate limitation may be swiftly put into place during a DDoS assault by making changes to WAF policies.
How do Open Source WAFs Work?
Through the filtering, monitoring, and blocking of harmful HTTP/S traffic heading to the web application and the prevention of any unauthorized data exiting the app, a WAF safeguards your web apps. WAF accomplishes this by following a set of rules that assist in identifying which communication is safe and which is malicious. Similar to how a proxy server serves as a middleman to safeguard a client's identity, a WAF, also known as a reverse proxy, functions similarly but in reverse, shielding the web application server from a potentially malevolent client.
A WAF uses pre-established rules and examines HTTP requests to identify malicious activity. It might be software, hardware, or services. The main elements of HTTP interactions that a WAF looks at are GET and POST requests. While GET requests are used to retrieve data from the server, POST requests are used to provide data to a server in order to change its state. WAFs evaluate PUT and DELETE requests, which send data to a server for updating and deletion, respectively.
The WAF searches the HTTP request content, query strings, and headers for malicious patterns. The WAF will stop the request and notify the security team if it discovers a match.
A WAF can analyze and filter the data in these HTTP requests using one of the three techniques below.
- Allowlisting: The WAF only authorizes requests that are known to be trustworthy; by default, it denies all requests. It offers a list of IP addresses that are considered secure. Blocklisting requires more resources than allowlisting. Allowlisting has the drawback of inadvertently blocking harmless traffic. It can be effective and cast a broad net, but it can be inaccurate.
- Blocking: Preset signatures are used in blocklisting to prevent harmful online traffic and safeguard website or application vulnerabilities. Malicious packets are identified by a set of rules. Because public websites and web apps frequently receive traffic from unknown IP addresses that aren't known to be malicious or benign, blocklisting is more suited for these types of websites. Compared to defaulting to trusted IP addresses, blocklisting has the drawback of being more resource-intensive and requiring more information to filter packets based on certain criteria.
- Hybrid Security: Hybrid security uses both blocklisting and allowlisting at the same time.
What are the Most Common Attacks Detected by WAFs?
A Web Application Firewall (WAF) is one piece of technology that can help defend online applications against threats. Incoming and outgoing traffic to and from a web application is monitored and controlled by a WAF, a security tool that stops assaults before they reach the web application. Rules and policies that examine traffic patterns and prevent any traffic that seems malicious are used to accomplish this.
These are some of the most frequent attacks that a WAF is intended to stop.
- SQL Injection Target: This method involves using web apps to target databases. Malicious SQL code can be injected by attackers into web application input fields, potentially granting them access to the database without authorization. By preventing any suspicious SQL queries and employing pattern-matching techniques to identify and stop SQL injection attempts, a WAF may stop SQL injection attacks.
- Attacks on Predictable Resource Location: One attack method for revealing concealed website functionality and information is predictable resource placement. An attacker can estimate file and directory names that aren't meant for public inspection by using brute force to make informed guesses. Because files and paths frequently follow similar naming patterns and live in regular places, brute-forcing filenames is simple. Logs, administrative site sections, configuration files, backup files, temporary files, demo apps, and sample files are a few examples of these. Sensitive information about the website, web application internals, database information, machine names, passwords, file paths to other sensitive places, etc., may be revealed by these files.
- XSS Attack: When a hacker inserts harmful code into a website or online application, it is known as a cross-site scripting (XSS) attack. By running this malware on the victim's browser, the attacker can steal confidential data or carry out other nefarious deeds. By removing potentially dangerous code from input fields and URLs, a WAF may stop XSS attacks.
- HTTP Flood DDoS: To target web servers and applications, hackers employ a distributed denial-of-service attack method known as HTTP Flood. In order to overload target servers with requests, HTTP floods aim to direct a lot of HTTP requests at a webpage.
- Cross-Site Requests Forgery (CSRF) Attack: An attack known as cross-site request forgery (CSRF) takes advantage of the trust that exists between a user and a web application. An attacker may deceive a user into doing an action on a web application that they had not intended to perform. By confirming the legitimacy of every request sent to the web application, a WAF can stop CSRF attacks.
- Server Side Request Forgery (SSRF): When an attacker uses a web security flaw to force a server-side application to send HTTP requests to any domain of their choosing, this is known as server-side request forgery (SSRF).
- Smuggling HTTP Requests: An attack method for interfering with a website's processing of a series of HTTP requests received from one or more users is HTTP request smuggling, sometimes referred to as HTTP desync attacks. It enables an attacker to "smuggle" a request to a web server without the web server and the attacker's devices noticing. Vulnerabilities in HTTP request smuggling are frequently of a significant kind, giving an attacker the ability to go around security measures, disrupt other user sessions, get sensitive data without authorization, and directly compromise other users of the application.
- Clickjacking: "Clickjacking" is a client-side attack that aims to trick users into clicking on something different from what they think they are clicking on. Hackers use vulnerabilities in the application supply chain to carry out this kind of attack by concealing malware or malicious code in a control that appears legitimate on a website. This is primarily done in JavaScript of third-party services, which are frequently overlooked by application standard security tools.
- Remote Code Execution (RCE) Attack: RCE attacks happen when a hacker has the ability to run any code on a target server. By preventing requests that include malicious code or by examining the application's behavior and blocking any requests that seem suspicious, a WAF can stop RCE attacks.
- File Inclusion Attack: An attacker can include a file from a distant server into a web application using this kind of injection attack. The attacker may be able to run arbitrary code on the web application server as a result. Through the denial of requests containing malicious code, a WAF may stop file inclusion attacks.
What are the Advantages of Free Open Source WAFs?
An open-source web application firewall (WAF) has several advantages, particularly for smaller organizations that may face financial constraints in procuring the services of prominent WAF companies. Open-source WAFs are extremely adaptable and configurable, making WAF technology accessible to companies that cannot afford commercial WAFs. In addition to potential cost advantages, an open-source project gives anyone the opportunity to personally examine the source code of an application, should they possess the inclination to do so. Numerous developers also have great admiration for and align themselves with the overarching principles of open-source software, which espouses a vision characterized by openness, transparency, and the cultivation of superior code quality. The main benefits of using an open-source WAF solution are listed below.
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Cost Benefits: Use an open-source Web App Firewall if you do not wish to spend a significant amount on web application security.
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No Vendor Lock-in: In addition to cost benefits, there is no possibility of vendor lock-in, which makes switching to a different product or provider difficult in the future. Depending on the underlying license, businesses can alter open source WAF solutions to build unique solutions
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Developer Community Support: Another important advantage is the developer community's normally high degree of dedication. Since a large number of independent developers collaborate on the code and regularly test it, flaws and vulnerabilities are frequently discovered and eradicated rapidly. This has a favorable impact on the software's quality, stability, and security.
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Start Small, then Grow: With open source, you may start small and rapidly with community versions before migrating to a commercially supported solution as your company's needs dictate. If the project does not require assistance, the community version can be used indefinitely. You have the option of evaluating many options, selecting the one that will work, and then scaling up with a commercial solution.
What are the Disadvantages of Free Open Source WAFs?
Besides the advantages of open source WAF solutions, there are some disadvantages as well. The primary drawbacks of open-source WAF solutions are as follows.
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Distributed Attacks: WAFs utilizing open-source frameworks and code are vulnerable to widespread flaws. Due to the fact that multiple systems utilize the same framework, hundreds of thousands of applications are susceptible to any newly discovered vulnerabilities. Once these vulnerabilities are uncovered, firms scurry to develop a fix before they are exploited by attackers. This indicates that open-source WAFs cannot be depended upon to stop attacks in real-time.
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Can be Bypassed: The majority of open-source WAFs utilize software with exploitable flaws. Open-source WAFs feature fail open and fail close events when excessive traffic is detected. During a fail open, a WAF does merely monitoring and so allows all traffic, including possibly malicious data, to pass through. In the event of a fail-close, all traffic is halted. A DoS or DDoS attack might circumvent the WAF, limiting full application access.
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Zero Day Vulnerabilities: A zero-day vulnerability is an attack that is unknown to a cybersecurity professional and only known to the attacker. Therefore, it takes time for a cybersecurity expert to develop a patch against a zero-day vulnerability. In the meantime, an attacker can compromise the system using this opportunity. The majority of open-source WAFs are unable to defend against these types of cyber attacks. To keep a WAF current with invasive zero-day attacks, developers must often and comprehensively change system rules, which is impossible.
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Configuration and Maintenance Issues: Open-source WAFs often need to be configured immediately after installation. In certain cases, they need considerably more labor than regular firewalls. For optimal protection, knowledge of both the open-source WAF and the application it is being installed on is essential.
If you lack this type of security knowledge in-house, you must outsource it, which is expensive. Given the value of the assets they protect, professionals in this field command a hefty salary. You wouldn't want a novice to muck up your cybersecurity frameworks via incompetence.
Open-source WAF network maintenance is extremely labor-intensive. Due to the adaptability of web apps, they are always evolving and need maintenance. Users are often in need of new features and regular updates. Not to mention the rapidly changing environment of computers.
What are the Differences Between ModSecurity and NAXSI?
While ModSecurity has more comprehensive and customizable rule set, NAXSI has simpler rule set with a focus on common attacks. Although the CRS ruleset for Modsecurity appears to be a solid foundation, it is likely that you would still need to fine-tune or add environment-specific rules. Keeping up with the whitelisting regulations for a particular application requires a great deal of knowledge and focus with NAXSI.
ModSecurity is supported by a wider range of web server platforms. But NAXSI is designed specifically for NGINX web server.
Moreover, ModSecurity offers more advanced features, such as real-time anomaly detection and data correlation than NAXSI offers.
When operating at a large scale, there are some compromises in performance that need to be considered when using ModSecurity with NAXSI. Particularly considering intricate and diverse URI pathways, method kinds, header choices, and so like. Although ModSecurity is more resource-intensive, potentially impacting performance and NAXSI is generally faster and less resource-intensive than ModSecurity, NAXSI may not be as effective against more sophisticated attacks.
What are the Differences Between Coraza and ModSecurity?
Coraza and ModSecurity are open-source web application firewalls (WAFs) specifically developed to safeguard web applications from malicious attacks. Nevertheless, they possess the following differences:
- Features: Both Web Application Firewalls (WAFs) include an extensive array of functions, such as rule-based filtering, anomaly detection, and IP reputation checks. Nevertheless, Coraza potentially offers a more contemporary and intuitive UI.
- Performance: Coraza asserts a substantial speed advantage over ModSecurity, with some reports indicating a 100-fold enhancement. Nevertheless, this assertion requires more independent verification.
- Compatibility: Coraza is specifically built to be compatible with the ruleset of ModSecurity v2. However, it does not presently support ModSecurity v3. Consequently, Coraza might be a more advantageous option for firms who are currently using ModSecurity.
- Language: Coraza is implemented using the Go programming language, while ModSecurity is implemented using the C programming language. As a result, Coraza has the potential to be quicker and more efficient, but it is also less developed and has not been extensively used.
What are Must-Have Features of the WAF?
When searching for a WAF for your server, several open source choices will appear in the search results. Open source projects give a clear image of what is required in a web application firewall and how they function, making this a suitable starting point.
The Open Web Application Security Project (OWASP) is a non-profit organization devoted to making software and server security "transparent so that individuals and businesses may make educated decisions".
You may learn about the top ten web application security issues on their wiki. The OWASP Top 10 emphasizes the most important security problems when designing or deploying a WAF for a server. This is the primary attack that a WAF is meant to prevent, and the list explains how a WAF secures your server.
Here are five aspects that are essential when selecting a WAF.
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Integration: As with other aspects of security, providing the proper protection begins with an analysis of the object being protected. You may already have assets protected by a hardware WAF. A cloud-based WAF can be placed in front of these devices to offload more common web attack traffic. You likely have some cloud-based assets, and if you're like the majority of businesses today, you're either pursuing or considering a multi-cloud strategy. In this circumstance, it is essential to consider an environment-independent security solution.
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Positive and Negative Security: It is necessary to consider many sorts of defensive postures, beginning with positive or negative security. A negative security posture presumes that all communication is permitted unless it contains a previously detected danger or attack. This is the most common deployment style for WAFs, and it is clear to understand why: a negative approach is significantly less likely to block genuine traffic. Clearly, the effectiveness of this strategy depends on the status of the security vendor's signature rule database and awareness of impending threats, since this defines the expected level of protection. If you adopt this posture, it is crucial that your databases keep up with evolving attacks as they are produced and mutate over time. This model will not detect zero-day threats since, by definition, these cyber attacks have no associated signatures.
The positive security approach, on the other hand, holds that traffic is rejected unless it is expressly approved. This strategy will identify zero-day threats as well as assaults using malformed packets or non-RFC-compliant traffic. A positive security strategy relies on traffic heuristics and automatic learning, enabling you to fit the profile to the traffic.
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Learning Mode: To achieve optimal security, it is essential that the service/device "learns" from its own experiences. This is a crucial aspect to which the service is well positioned to contribute. Because security teams are frequently sufficiently isolated from development teams, they may lack knowledge of program components or what defines "acceptable conduct". Learning mode observes the traffic traversing the device and gives recommendations regarding which relaxation rule if any, should be implemented.
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Customization: Vulnerabilities and attack signatures are common WAF components. It is crucial that businesses remain at the forefront of vulnerability research and periodically provide signatures for securing vulnerable services and open source libraries. It is essential to be able to include signatures from other sources, such as industry ISACs and third-party vendors. Additionally, it should be straightforward for you to add your own signatures to the WAF rules based on your own expertise and knowledge.
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Easy to use: You should be able to choose from a wide variety of controls and apply them in granular form, including the ability to apply policies to groups of apps. While deploying a WAF may be a given, having a WAF that can be readily updated and maintained is a competitive advantage. Due to the ongoing evolution of threats, a WAF must be adaptable enough to stay up.
How to Choose the Right Open Source WAF?
Understanding the various performance metrics is essential to selecting the appropriate WAF solution for your company. To determine the best choice for your needs, you should first filter this external data on WAF performance according to your internal requirements.
When selecting among WAF providers, you should take into account the following important factors.
- Security Performance: The WAF's ability to recognize and stop harmful requests.
- Security Measures: The many security measures offered and the dangers they guard against,
- Type of Deployment: Whether the solution is host-based (software WAF operating on-premises or in the cloud), network-based (hardware placed locally), or cloud-based (turnkey SaaS option).
- Ease of Use: This encompasses interface design, assistance, and documentation.
- Integration: The degree to which the WAF works with your current technology stack, especially with regard to your security solutions.
- Web Application Performance: Making sure the WAF doesn't adversely affect end users by drastically slowing down web apps.
- Cost: This covers all ownership expenses, including maintenance and other elements, in addition to the software subscription.
- Scalability: Make sure the system can handle a significant increase in web app traffic.
Furthermore, the following questions may be answered by taking into account these criteria while assessing web application firewall options:
- Which models of deployment are supported?: The top WAFs provide a variety of deployment choices, allowing them to function in the cloud or on-premises, with fully managed or self-managed methods, depending on what the company needs.
- How is traffic filtered by the WAF?: A WAF's capacity to identify complex assaults that are often missed by generic firewalls improves with the amount of information it can take into account while analyzing traffic.
- What is the required level of efficiency for the WAF? To prevent depriving apps of the infrastructure resources they require to function, all WAFs should execute effectively.
Scalability should be taken into account while selecting a web application security solution, in addition to the previously mentioned factors. In what ways will the WAF need to grow going forward? Will apps running on hybrid and multicloud architectures need to be supported? Will API support be required? The ability to safeguard both web apps and APIs will become increasingly important as they become more integral to app-to-user interactions.
What are Use Cases for Open Source WAFs?
Web application firewalls improve online organizations' security performance. Businesses suffer greatly from breaches and other security issues in a variety of ways. WAFs harden the enterprise perimeter by preventing unauthorized traffic in order to defend against them.
The article's five case studies demonstrate how WAFs may assist in resolving network security issues in a variety of sectors.
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TechnoCross NTT: Since its founding in July 1985, NTT TechnoCross has offered its clients cutting-edge technology and creative IT solutions. NTT TechnoCross, a division of the well-known telecom provider Nippon Telegraph and Telephone (NTT), uses its network, security, and cloud technologies to help clients build and run their businesses. The firm currently has over 2,000 people working for it.
By fully controlling the reaction to cyberattacks, Imperva's cloud WAF solution assisted NTT TechnoCross in improving the functionality of its website and reducing operational strain. TechnoCross maintained the use of their unique rules with Imperva, which expedited the process for all NTT organizations while guaranteeing IPv6 compatibility in a short amount of time.
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SHOPYY: When SHOPYY was first launched in 2018, its lofty objective was to become China's biggest e-commerce platform for independent companies. To make it easier for small companies and wholesalers to migrate their stores online, the team provides technical help.
The founder and CTO, Yuanming Chen, states, "Our web application firewall has developed a specialized security defense system for us, greatly increasing SHOPYY's security and providing peace of mind to all our users."
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Steelcase: One well-known producer of office furniture is Steelcase. Steelcase, which was founded in 1912, has a strong focus on user-based research in order to design spaces for the top enterprises worldwide. The corporation, which employs over 10,000 people, has built a global distribution network that consists of direct end consumers as well as independent and company-owned dealers.
To provide its e-commerce platform more protection, the business installed Fortinet FortiGate next-generation firewalls. By helping to identify and block unwanted traffic, the firewalls provide the business with a better understanding of how its customers behave.
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Canterbury School: Canterbury is a coed residential and day school for students in grades 9-12 that was established in 1915. About 200 professionals work at Canterbury School in a variety of roles.
Canterbury needs a more sophisticated security solution that could safeguard school data and maximize network security performance. The organization's security needs were satisfied by SonicWall's firewall solution, which guaranteed flawless data protection and raised the school's profile. Security precautions across remote locations were made feasible by the WAF solution's integrated VPN and Capture Security Center, a single-pane-of-glass administration and reporting system.
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Aevitate: Aevitae is a well-known insurance provider with headquarters in the Netherlands that offers direct and corporate insurance solutions. Aevitae has processed over 800,000 paper and 6 million digital claims while serving thousands of consumers with a small staff of 200.
To solve the security issues with the current paradigm, the insurance company used Barracuda CloudGen Firewall and Barracuda CloudGen WAF on-premises and on the Microsoft Azure cloud platform. Barracuda suggested utilizing the Premier Partner Data Unit, and the three businesses joined together to put in place a security solution that met Aevitae's needs. As a result, whenever the need arose, Aevitae was able to leverage the firewall's knowledge of cloud-based services and the Data Unit's infrastructure experience.
Can you Integrate Open Source WAFs with Cloud Services?
Yes. Cloud-based WAFs, which interface with load balancers or cloud virtual networking services, can be used by cloud-hosted applications to filter web traffic. Although deploying and maintaining cloud-based WAFs doesn't require a huge staff, they usually don't provide comprehensive threat context.
The location of a company's web apps influences the WAF deployment style it chooses. For instance, a cloud-based WAF only functions when apps are set up in the cloud. Network- and host-based WAFs often require more setup and management if maintenance is a factor when selecting a deployment architecture, while cloud-based WAFs only require a DNS or proxy change.
AWS WAF is one fully managed, flexible WAF solution that helps protect web apps from frequent online attacks. Because it is simple to incorporate into current infrastructure, it is perfect for AWS users.
On the ModSecurity engine, AWS WAF is built. The original code for ModSecurity was made available more than 20 years ago, making it one of the first open-source WAFs. ModSecurity has undergone several significant iterations over the years, and because it is open-source, numerous businesses have been able to incorporate it into their web server applications.
By acting as a reverse proxy and being positioned between the client and the web server, ModSecurity functions. To ascertain whether incoming requests are malicious or not, it intercepts them, examines them, and applies the ModSecurity core rules.
ModSecurity WAF is an open-source, highly configurable solution; AWS WAF connects with other AWS services and offers sophisticated security capabilities; and open-appsec is a proactive WAF solution that uses machine learning to defend your web application against online threats.
What is the Difference Between Open Source WAF and Open Source Firewall?
Although a WAF is a specific type of firewall, the word "firewall" is typically used to describe something else. The following are the main distinctions between a WAF and a conventional firewall:
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Protection Scope: A WAF is a targeted solution intended to defend an organization's web apps from intrusions. An NGFW or comparable firewall, on the other hand, is designed to keep an eye on all incoming traffic that crosses a network border, including application and web traffic as well as other types of network traffic.
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Layer of OSI: A Layer 7 security solution called a WAF looks for indications of SQL injection and other web application threats in malicious requests. Traditional firewalls mostly function at Layers 3 and 4 of the OSI model, looking at IP addresses and TCP/UDP ports, while NGFWs may also function at Layer 7, providing application awareness and granular access restrictions.
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Main Point of Interest: WAFs are designed to identify exploits, searching for efforts to attack weak web applications. Firewalls, on the other hand, search network traffic for harmful content or data exfiltration and block unauthorized IP addresses and protocols.
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Network traffic versus application traffic: Conventional network firewalls reduce or stop illegal access to private networks. Any additional attempts at access are prohibited by firewall policies, which specify the traffic that is permitted to enter the network. Unauthorized users and assaults from people or devices in less secure zones are two examples of network traffic that this helps to avoid.
Application traffic is the specific objective of a WAF. It safeguards apps and HTTP and Hypertext Transfer Protocol Secure (HTTPS) communication in network areas that are visible to the internet. This protects companies from risks including SQL injection attacks, distributed denial-of-service (DDoS) assaults, and cross-site scripting (XSS) attacks.
| WAFs | Firewalls |
|---|---|
| WAF is concerned with making sure that application network communication is secure. | A firewall strains a network in order to monitor and safeguard traffic. |
| WAF is positioned in front of servers and applications, enabling it to provide defense against any threat intended to target servers. | By placing a firewall close to a network's edge, it creates a barrier between known and reliable networks and any unidentified ones. |
| WAFs frequently focus on protecting servers and HTTP/HTTPS applications from intrusions. | Firewalls are designed to either permit or forbid network access in order to stop unauthorized users from accessing networks. |
| WAF primarily targets the layer 7 (Applications), which is closest to the user. | Firewalls concentrate on layers 3 (network) and 4 (transport) of the OSI model. |
| WAFs don't concentrate on limiting or controlling access. | The main function that a firewall performs is access control. |
| WAFs execute heuristic, signature-based, and anomaly detection algorithms. | Stateless/Stateful Inspection, Packet-Filtering, and Proxy algorithms are all implemented by standard firewalls. |
| WAF functions in two distinct ways: Mode of Passivity, Mode of Active Inspection | Additionally, Standard Firewall has two modes of operation: Mode of Routeing, Mode Transparent |
| Threats including SQL Injection, DDOS, XSS, and cross-site scripting assaults are stopped by WAF. | A firewall prevents access to pornographic or dubious information from school computer laboratories and prevents users from signing in to a computer lab's local area network (LAN). |
Table 1. WAF vs Firewall