Your Guide to Web Application Penetration Testing

Due to the growing number of cyber threats, companies are constantly looking for new ways to protect their web apps. Web application penetration testing is one of those techniques, and it has already become an essential part of any solid protection strategy.

The popularity of cybersecurity services is constantly growing, and this isn’t just talk. Research from Markets and Markets projects the pen testing industry will increase from $1.7 billion in 2020 to an impressive $2.7 billion by 2027. That’s why we suggest you discover what penetration testing for a web application is, why it is important, and what protective value it adds.

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What Is Web Application Penetration Testing?

Penetration testing, often abbreviated as “pen test,” is a simulated cyber attack against computer systems to check for exploitable vulnerabilities. In the context of web applications, it involves testing websites, web applications, and online services for security weaknesses that hackers could use. 

Penetration testing for web applications can involve the attempted breaching of any number of application systems (e.g., application protocol interfaces (APIs), frontend/backend servers) to uncover web app vulnerabilities, such as unsanitized inputs that are susceptible to code injection attacks.

Why Is Web Application Penetration Testing Important? 

E-commerce, online banking, healthcare, Enterprise Resource Planning (ERP), Content Management Systems (CMS), billing, accounting, and payrolling software usually come in the form of a web app. Since these web applications store and transfer sensitive data, it is crucial to keep these apps secure through the software development lifecycle, particularly those that are publicly exposed to the World Wide Web.

Web application penetration testing, in turn, is important for the next reasons: 

• Identifying Unknown Vulnerabilities: Even with the most thorough security protocols, some weaknesses can slip through the cracks. Penetration testing proactively seeks out these blind spots, uncovering vulnerabilities that automated tools or routine checks might miss.
• Evaluating Security Policies: It’s one thing to have web and mobile application security policies in place; it’s another to know they work as intended. Pen testing puts these policies under the microscope, testing their effectiveness in real-world scenarios. This process helps ensure that theoretical defenses hold up under actual attack conditions.
• Testing Publicly Exposed Components: The digital façade of a company, including its firewalls, routers, and DNS systems, is often the first target for attackers. Penetration testing scrutinizes these components, identifying weaknesses that could be exploited and assessing the resilience of the perimeter defense.
• Identifying the Weakest Link: Attackers often look for the path of least resistance. Pen testing helps pinpoint the most vulnerable aspects of a system, which could serve as a gateway for broader attacks. Understanding these weak points allows for targeted strengthening of defenses.
• Uncovering Data Theft Loopholes: Data is a prime target for cybercriminals. Web application penetration testing searches for loopholes that could lead to data theft, including insecure data transmission, improper storage practices, and other vulnerabilities that could be exploited to access sensitive information.

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Types of Penetration Testing for Web Applications

Penetration testing for web applications can be categorized into various types, each focusing on different aspects of web security. These tests aim to identify vulnerabilities that could potentially be exploited by attackers. Here’s a breakdown of the primary types of penetration testing specifically tailored for web applications:

1. Black Box Testing

In black box testing, the tester has no prior knowledge of the application’s internal workings. This approach simulates an external cyber attack and focuses on identifying vulnerabilities that can be exploited from the outside, without any insider information. It’s useful for testing the application’s external defense mechanisms.

2. White Box Testing (Also Known as Clear Box Testing or Glass Box Testing)

White box testing provides the tester with complete information about the application, including source code, architecture diagrams, and credentials. This comprehensive knowledge allows for a thorough examination of the application for vulnerabilities, including those that are difficult to detect from the outside. It’s effective for assessing the application’s internal security and logic.

3. Gray Box Testing

Gray box testing is a hybrid approach that offers the tester partial knowledge of the application’s internals. This might include limited access or an overview of the architecture and protocols but not full source code access. Gray box testing balances the depth of white box testing with the realism of black box testing, providing a well-rounded security assessment.

4. Static Application Security Testing (SAST)

SAST involves analyzing the source code, byte code, or binaries of an application without executing it. This type of testing is designed to identify security flaws at the code level, making it possible to find vulnerabilities early in the development cycle.

5. Dynamic Application Security Testing (DAST)

DAST focuses on testing an application during its execution, simulating attacks against a running application. This approach is effective for identifying runtime and environment-related vulnerabilities, such as those related to authentication and session management.

6. Interactive Application Security Testing (IAST)

IAST combines elements of both SAST and DAST, analyzing the application from within during runtime. This method provides deep insight into how data flows through the application and how vulnerabilities can be exploited, offering a comprehensive view of the application’s security posture.

7. API Penetration Testing

Given the critical role of APIs in modern web applications, API penetration testing specifically targets the security of web APIs. This involves testing methods, data handling, authentication mechanisms, and the way APIs interact with other components of the application.

8. Client-Side Penetration Testing

This testing method zeroes in on the weak spots found in client-side technologies, including HTML, JavaScript, and CSS. It aims to identify security issues that could be exploited through the user’s browser, such as cross-site scripting (XSS) and cross-site request forgery (CSRF).

Each type of penetration testing offers unique insights into the security vulnerabilities of web applications. By employing a combination of these testing approaches, organizations can achieve a comprehensive assessment of their web application’s security, uncovering and mitigating potential vulnerabilities to prevent cyber attacks.

Your next read – Recognise App Security Vulnerabilities Beforehand With Application Threat Modeling

Web Application Penetration Testing Methodology

Web Application Penetration Testing follows a structured approach to identify and exploit vulnerabilities within web applications. This methodology is designed to systematically assess the security of web applications by simulating attacks that could be carried out by malicious actors. Here’s an overview of the typical phases involved in a Web Application Penetration Testing Methodology 2025:

1. Planning and Reconnaissance

• Objective Setting: Define the scope and objectives of the penetration test, including which applications and functionalities will be tested.
• Information Gathering: Collect as much information as possible about the target application and its environment. This includes understanding the application’s technology stack, mapping out the application, and identifying potential entry points. To gather crucial data, the following web application penetration testing tools and techniques are employed:

a. Passive Reconnaissance: Leverage search engines, social media, and public sources for information on the organization, its employees, and potential security gaps.

b. Active Reconnaissance: Utilize tools such as Nmap and automated web crawlers to map out the application’s structure, along with its ports and services.

2. Scanning and Enumeration

• Automated Scanning: Use automated tools to scan the web application for known vulnerabilities, such as outdated software versions, misconfigurations, and common security flaws.
• Manual Enumeration: Manually inspect the application for logical vulnerabilities that automated tools might miss. This involves examining the application’s behavior, identifying user roles, and understanding data flow.

3. Vulnerability Analysis

• Identify Vulnerabilities: Analyze the results from both automated scanning and manual enumeration to identify potential vulnerabilities within the application.
• Risk Assessment: Assess the severity and potential impact of identified vulnerabilities. This helps in prioritizing which vulnerabilities to exploit first.

4. Exploitation

• Exploit Vulnerabilities: Attempt to exploit identified vulnerabilities to determine if unauthorized access or other malicious activities can be achieved. This step verifies if the vulnerabilities are exploitable in real-world attack scenarios.
• Advanced Exploitation Techniques: In some cases, chaining vulnerabilities or using advanced exploitation techniques may be necessary to gain deeper access or demonstrate the full impact of a security flaw.

5. Post-Exploitation

• Determine Impact: Once access is gained, evaluate what type of data can be accessed, the level of control obtained over the system, and how the vulnerability could be leveraged for further exploitation.
• Persistence: Test if the access can be maintained, simulating an attacker’s ability to persist within the application environment undetected.

6. Analysis and Reporting

• Compile Findings: Document all findings, including the vulnerabilities discovered, the exploitation process, and the potential impact.
• Recommend Remediations: Provide detailed recommendations for mitigating the identified vulnerabilities, prioritized by their risk level.
• Report Delivery: Deliver a comprehensive report to stakeholders, outlining the vulnerabilities, evidence of exploitation, and recommendations for security enhancements.

7. Remediation and Re-Testing

• Remediation Verification: After vulnerabilities have been addressed, cybersecurity developers verify the effectiveness of the remediation efforts through re-testing.
• Continuous Assessment: Recommend that web application penetration testing be conducted regularly, not just as a one-time activity, to ensure ongoing security as the application evolves.

This structured methodology ensures a thorough assessment of web application security, uncovering vulnerabilities that could be exploited by attackers and providing actionable insights for enhancing the application’s security posture.

How Is Penetration Testing for Web Apps Done? 

Penetration testing for web applications involves a targeted approach to identify and exploit vulnerabilities. Here’s how web penetration testing could be executed for an e-commerce app:

1. Define the Scope: Clearly outline the boundaries of the test, focusing on the e-commerce platform, including its user authentication, product listing, shopping cart, checkout process, and any associated APIs.
2. Gather Information: Use tools and techniques to collect data about the e-commerce platform, such as the web server details, application framework, and third-party plugins. This stage might involve automated scanning to identify visible application endpoints and services.
3. Automated Scanning: Utilize automated tools to scan the e-commerce platform for known vulnerabilities, such as SQL injection, cross-site scripting (XSS), and security misconfigurations. Tools like OWASP ZAP or Burp Suite can be handy.
4. Manual Testing and Exploitation: Focus on areas that automated tools might miss. For example, manually test for business logic vulnerabilities that could allow unauthorized access to other users’ shopping carts or manipulate product prices.
5. Exploit Identified Vulnerabilities: Attempt to exploit vulnerabilities to assess their impact. For instance, if an SQL injection vulnerability is found in the product search feature, try to extract sensitive database information or manipulate the query to gain unauthorized access.
6. Session Management Testing: Evaluate the security of user sessions by attempting to hijack or manipulate session cookies to impersonate users.
7. Data Access and Exfiltration: Explore how much sensitive data can be accessed or exfiltrated through exploited vulnerabilities, such as customer personal data, credit card information, or internal application data.
8. Maintain Access: Assess if and how an attacker could maintain access to the system, perhaps by creating backdoor accounts or exploiting weaknesses in the application’s session management.
9. Document Findings: Prepare a detailed report outlining identified vulnerabilities, how they were exploited, the potential impact, and evidence of the exploitation process.
10. Recommend Remediations: Provide actionable recommendations for each identified vulnerability, prioritizing them based on their severity and impact on the e-commerce platform.
11. Re-Testing: After remediations are applied, conduct a re-test to ensure vulnerabilities are adequately addressed, and no new issues have been introduced.

This web pentesting roadmap provides a comprehensive assessment of the e-commerce web application’s security posture, focusing on identifying and addressing vulnerabilities to enhance the platform’s defense against potential cyberattacks.

Web Application Penetration Testing Tools

Web application penetration testing tools are a vital part of any organization’s security strategy. These tools simulate attacks on a web application in order to identify vulnerabilities and assess the effectiveness of the application’s defenses. Let’s look at the top penetration tools used for web applications in the industry today: 

John The Ripper

A popular tool for penetration testing, used to crack password hashes. It can perform dictionary attacks, brute-force attacks, and hybrid combinations. John the Ripper analyzes password hashes and, if successful, reveals the cracked password along with the number of attempts needed.

SQLmap

SQLmap is a penetration tester’s secret weapon against SQL injection vulnerabilities, one of the most common web application security flaws. This command-line warrior automates the entire process, from detecting these vulnerabilities to exploiting them with lightning speed and efficiency.

Wireshark

Wireshark, a top network protocol analyzer, lets you capture and dissect live or recorded traffic. The tool deeply analyzes protocols, then exports data (XML, CSV, etc.) for further exploration.

Nessus

This vulnerability assessment tool helps testers identify vulnerabilities, configuration problems, and even the presence of malware on web applications. This tool, however, is not designed for executing exploitations but offers great help when doing reconnaissance. 

Nmap

Nmap or Network Mapper is more than a scanning and reconnaissance tool. It is used for both network discovery and security auditing purposes. Aside from providing basic information on the target website, it also includes a scripting engine that can be used for vulnerability and backdoor detection and execution of exploitations. 

Metasploit

Metasploit stands out among other penetration testing tools for web applications. The reason is that this is actually a framework and not a specific application. You can use it to create custom tools for particular tasks. You can use it to select and configure the exploit, payload, and encoding schema to be used, then execute the exploit.

Aircrack-ng

Aircrack-ng is a go-to tool for cracking WEP/WPA/WPA2 keys on wireless LANs, beloved by penetration testers since 2002 for its efficacy in testing wireless network security. Beyond testing, Aircrack-ng helps identify unsecured networks, crack weak or unprotected Wi-Fi passwords, and decrypt traffic on encrypted networks.

Burp Suite

We’ve mentioned Burp Suite a couple of times earlier, and this is because this tool is an all-in-one platform for testing the security of web applications.  It has several tools that can be used for every phase of the testing process, including Intruder for fuzzing and brute-forcing, Repeater for manipulating requests and responses, and Sequencer for identifying predictable elements.

Penetration Testing Certifications

While the concept of penetration testing seems simple at first glance, building a career in this field requires specific certifications. Let’s review them briefly.

Foundational Certifications

• CompTIA PenTest+: This entry-level certification establishes basic knowledge in penetration testing methodology, vulnerability scanning, legal aspects, and report writing.
• EC-Council Certified Ethical Hacker (CEH): This vendor-neutral certification covers ethical hacking methodologies, tools, and techniques across various IT systems, including web applications.

Intermediate Certifications

• Offensive Security Certified Professional (OSCP): This hands-on certification emphasizes practical skills in web application penetration testing through a real-world lab environment simulation.
• Certified Ethical Hacker Practical (e|PH): This builds upon CEH knowledge through a performance-based exam to demonstrate web application penetration testing skills.
• GIAC Penetration Tester (GPEN) certification: This delves deeper into penetration testing practices, vulnerability analysis, and risk assessment.

Advanced Certifications

• Certified Penetration Tester (CPT): This vendor-neutral certification emphasizes advanced penetration testing skills across various IT systems, requiring strong technical knowledge and experience.
• Certified Expert Penetration Tester (CEPT): This demands in-depth expertise in penetration testing across various systems, including web applications.
• GIAC Exploit Researcher and Advanced Penetration Tester (GXPN): This focuses on advanced exploitation techniques, custom exploit development, and in-depth research skills.

Specialized Certifications

• Certified Mobile and Web Application Penetration Tester (CMWAPT): This focuses on vulnerabilities specific to mobile and web applications, emphasizing mobile app security testing principles.
• GIAC Certified Web Application Penetration Tester (GWAPT): This highlights advanced web application penetration testing skills and covers secure coding practices for developers.
• Licensed Penetration Tester Master (LPT) Certification: This rigorous 2-year program designed for seasoned professionals seeking mastery in penetration testing and network security, emphasizing practical experience through projects and labs.

Automated vs. Manual Pentesting

Automated and manual web application penetration testing are two different approaches to conducting a penetration test.

Automated pen testing involves using specialized software tools to scan a system for vulnerabilities and perform attacks. This approach is fast and efficient, and it can cover a large number of vulnerabilities in a short amount of time. However, it can also produce false positives (i.e., reporting vulnerabilities that do not actually exist) and may not be able to identify all vulnerabilities, especially those that require a human touch to discover.

Manual pen testing, on the other hand, involves a skilled security professional manually testing a system for vulnerabilities and exploiting them. This approach is slower and requires more human effort, but it can be more thorough and accurate. Manual pen testing can uncover vulnerabilities that automated tools might miss, and it allows the tester to think creatively and adapt to unexpected situations.

While both approaches have pros and cons, they can be used together successfully to create a more thorough test. In fact, some companies find that combining the two approaches gives them the best possible results by bringing together the strengths of each method.

Read our guides on how to hire a cybersecurity developer and site reliability engineer. 

Web Application Penetration Testing: Summing Up 

Web applications are convenient, cost-effective, and value-adding. However, most systems are publicly exposed to the Internet, and the data can become easily available to those who are willing to do a bit of research. What’s more, even the most advanced web applications are prone to vulnerabilities, in both design and configuration, that hackers might find and exploit. Because of this, the web application penetration testing roadmap should be a priority.

Relevant has helped more than 200 companies with setting up teams of remote developers and site reliability engineers with industry-specific expertise and a product-oriented mindset. Our cybersecurity developers would also be glad to help you run a web application penetration testing and get an insightful look into the possible vulnerabilities. 

Contact us now to get a quote for penetration testing for your web app. 

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