web application pen testing

Web Application Penetration Testing: Steps, Methods, Techniques, Checklist & Tools

Page Contents

The web has changed from having handy code that could be understood easily to having large blocks of difficult to comprehend code. This has forced the hand of developers and UI designers to change how the web is made even if that does not seem like the best option.

Moreover, the internet (browser, you think?) has never truly been a safe place. And in recent times, it has only gotten worse – especially for businesses. Given that 9 out of 10 hackers can attack users through organizational web applications, it leaves much to be desired in the cybersecurity sphere at an enterprise level.

After all, issues like SQL injection or cross-site scripting can put all users at risk, even if they take all security measures. What is more concerning is that about 50% of internal application vulnerabilities are critical or high risk, while this figure is pegged at 32% for internet-facing applications. In short, nobody is safe.

As such, the onus lies on the developers to perform application security testing to detect and mitigate the effects of such risks. 

Reason is naturally simple.

A decade ago, we saw a lot of websites based around HTML and CSS, nowadays it’s become commonplace to have applications powered by a lot of JavaScript that run across multiple devices. 

Asynchronous operations are one of the features that distinguish current web applications from document-based websites. These asynchronous operations allow for partial content updates, data caching and even offline usage.

Each web application is different in numerous ways, including: 

  • size and complexity, 
  • code-base, 
  • technologies used, 
  • corporate policy. 

However, each phase is partially fleshed out depending on the testing requirements for that specific web application or project. 

Rising Top security risks to applications

According to the 2018 Verizon Data Breach Report, 19% of data breaches were caused by web applications. These data breaches resulted in 96% of all stolen records containing personally identifiable information (PII).

Source: the distribution of vulnerabilities by severity over time and 2021 is already on its way to make a new record.

  1. Web applications continue to face an onslaught of attacks from attackers who rely on poorly secured client-side products. In fact, web applications are one of the most common hacking vectors mentioned in the 2021 Verizon DBIR report
  2. In the year 2020, 4th highest recorded vulnerability count (more than 17,000) discovered in production code.
  3. As per Snyk, nine out of the top ten images that have been downloaded the most in 2018 contain more than 50 vulnerabilities. These were also open source projects, which means that developers worldwide downloaded these images and containers multiple times per month on average with their respective applications – a risky business indeed.
  4. A study carried out by F5 rigorously examined users’ trends, patterns, and behaviors when it comes down to sharing and updating applications. API breaches caused by third-party integrations or problems were the key drivers.

One might say it wasn’t always like this, but there was a time when endpoint protection and network security were the ultimate protective measures.

With the advent of the proliferation of mobile and cloud technology along with the trend in bringing more business applications into the fold, network security efficacy was remarkably minimised as well. What worked in the past – relying on a “perimeter-centric approach” due to its effectiveness of segmentation thus increasing overall security efficiency – no longer sufficed at that point.

Fast-forward to now, where organizations are reaching new heights of business success by relying on application programming interfaces (APIs). Before this time, most businesses were relying on the internet to move their products and services, but the issue was nearly everything was moving at one speed. Now that we have APIs involved – things are moving at multiple speeds. This way, an organization can continue receiving orders for its various goods and services, but it also has the opportunity to utilize different ways of getting in touch with customers who will want full interaction with the company’s product or service.

A web application vulnerability assessment is required to identify and mitigate potential threats. With the increasing number of transactions using web applications, it has become necessary to have a safe and secure platform for data/information transactions over the internet.

You must not forget one thing – the security which is vital for your application

This will make your developers go that extra mile to ensure that your app does everything it’s supposed to but with added layers of protection too. Remember this guy called ‘hacker’? They might be interested in what data you are storing in your application and some of these hackers are more dangerous than you realize!



So, what is Web Application Penetration Testing?

Web application security pen testing is the process of assessing and determining which parts of your web application need to be reinforced to help ensure that it will remain unaffected by malware, data breaches, or cyberattacks.

The goal is to test how a web application will react when it receives unexpected input, which is usually crafted, by a malicious user, to exploit a flaw in your Web application after decoding its protocol.

 It’s better to be safe than sorry when it comes down to user safety.

In addition to reading the source code, successful application security testing also includes checking end-to-end input validation and output encoding and ensuring that important components of the application logic are implemented securely.

What are the six types of Penetration Testing?

  • External Vs Internal Pen Testing
  • Network Pen Testing
  • Social Engineering Penetration Testing
  • Physical Pen Testing
  • Firewall Pen Testing
  • Wireless Pen Testing

What is External Penetration Test?

What are the examples of external penetration tests?

What is Internal Penetration Test?

What are the examples of internal penetration tests?

What is Network Penetration Test?

What are the examples of network penetration tests?

What is Social Engineering Pen Test?

What are the examples of social engineering penetration tests?

What is Physical Pen Test?

What are the examples of physical penetration tests?

What is Firewall Pen Testing?

What are the examples of firewall penetration tests?

What is Wireless Pen Test?

What are the examples of wireless penetration tests?

What are the 3 main benefits of Web application Pen testing?

A web application needs to be tested from a legal, privacy, and environmental standpoint, just like any other branch of a business. 

A lot of these tests will involve finding out how the app handles its security and privacy measures and how well it has been crafted against social engineering tactics used by hackers. Web application assessment involves lots of handwork and understanding of technical aspects under the hood of a website that makes it click.

Benefit #1: Since mistakes always happen, it is important to ensure security measures in advance.

With extensive security testing, you have the opportunity to discover new aspects of your application that perhaps wouldn’t have been revealed otherwise. One of the most exciting benefits of this is finding and identifying vulnerabilities in your applications that might otherwise not have been identified.

Benefit #2: IT Security Compliance for Your Business

For business owners, it is crucial to make sure their applications work equally as hard on the inside as they look on the outside. This means that regular app security testing is a reputable step for ensuring you are meeting compliance to current laws – others take note.

Benefit #3: Finds loopholes in your system

Security testing lets you check how well current security measures stand up against the ongoing threat of cyber attacks. By finding out the weak areas, application security vulnerability testing experts alert you to the possible risks before they become a real issue. In short, it detects any gaps or lack of efficiency in your application.

Source: 75% of cyber attacks are done at the web application level.

What are the 4 features that should be reviewed during a web application security test?

Server configuration

Securing your web servers by implementing encryption protocols and analyzing Web server configurations would be the best thing you can do to protect yourself from defects. This will ensure that all ports are logs-free of all data transmissions.

Input/output checks

OWASP top 10 causes application security threats like SQL injection and cross-site scripting by abusing input or output handling.

Session Security

Application security is important for preventing bugs such as the possibility of a hacker logging into a user account without their knowledge. This could result in anything from unauthorized withdrawals from an account to private data release, including identifying information. It’s always vital to ensure that your applications are secure and everything is working properly.


The authorization testing involves testing the ability of the application to protect against privilege escalation attacks.

What is the importance of web application security testing?

Web applications are akin to delicate dishes at multi-star restaurants. 

They are complex and need an assortment of ingredients to achieve the perfect balance. The implication is that they rely on many third-party libraries to make them perform optimally and make sure their customers are satisfied. 

It is worthwhile to mention that business IT infrastructure is no longer simply about network security or data security. Both of these have grown in importance but web applications now have to be considered first and foremost among the software applications a firm has deployed online at any given moment if they are to protect themselves from hackers trying to gain access information or to corrupt corporate data.

It may come as no surprise that a recent nCipher Security report showed that one in five Americans doubt the security of their personal information.

And they have valid reasons to cement their belief. Common scenarios like the following could be ideal for external cyber attacks. 

  • Document management systems give companies a way to organize and store documents as well as digital files. The documents will have a web address, which can be accessed in order to view the documents.
  • Corporate team members can access the email system from their corporate portal linked to a mail server.
  • Cyber-attacks on sales/CRM software used via online portals are also a massive threat.

Combining this intricate construct with multiple pages, forms, and videos can be a recipe for disaster if you don’t have the right ingredients or someone who knows how to use a scalpel when they prepare your final dish (the web application in this scenario).

Like a well-executed soufflé, the secret to creating a successful web application is to make sure it’s properly tested before serving it up to an eager customer base. This helps ensure that the users will be able to find the mix of features and functionalities that work in tandem with their needs and expectations.  

Web application vulnerabilities occur on account of security flaws or defects embedded in the application. Attackers generally try to target web applications with insecure admin tools, CMS’s and SaaS products. A recent report from 2020 Forrester revealed that the majority of external attacks are carried out by exploiting vulnerabilities in software or web applications.

What are the key Web Application Vulnerabilities?


Web application vulnerabilities are as dynamic as technology. The National Vulnerability Database (NVD) discovered 19,138 vulnerabilities in 2021, which indicates a steady incline from 18,362 in 2020 and 17,382 in 2019. This statistic shows how malicious entities continue to reevaluate their techniques to keep up with the trends.

Following is the list of common web application vulnerabilities:

  • Injection flaws
  • Authentication weaknesses 
  • Poor session management 
  • Broken access controls 
  • Security misconfigurations 
  • Database interaction errors 
  • Input validation problems 
  • Flaws in application logic

Keeping in view the changing landscape of online vulnerabilities, penetration testing is an excellent way to stay abreast of security requirements.

Pen testing?

What is Penetration Testing? And Why Is It Necessary?


Penetration testing, or pen testing, is a simulated cyberattack against a web application or IT infrastructure to identify and secure vulnerabilities. It also helps validate all the security measures to protect the application.

The primary difference between pen testing and vulnerability testing is that web application pentest steps could be manual or automated. On the other hand, vulnerability testing tools are mainly automated.

Now that one understands the basic definition of penetration testing, let’s take a look at why it is important. 

What are the five key reasons for pen testing?

  1. Identify Security Risks: It evaluates an organization’s ability to secure its networks, applications, and other elements of the IT infrastructure. It also shares insights on assets that are at risk, especially those that require protection.
  2. Manage Vulnerabilities Intelligently: Pen testing takes a detailed look at the existing vulnerabilities and quantifies them by mapping them against their impact. By doing so, businesses can prioritize risks that need immediate attention.
  3. Promote a Security-First Mindset: Most organizations follow a corrective approach to responding to cybersecurity breaches. With pen testing, such a strategy can also subsume a preventive to be more holistic.
  4. Conduct SWOT Analysis on Security: Pen testing reviews the existing security programs in place and identifies the strengths, weaknesses, and opportunities therein. It also imparts confidence in the existing security framework.
  5. Adhere to Regulatory Requirements: By following a security auditing routine, businesses can ensure adherence to the local or governmental regulatory framework and follow due diligence. It will also offset any liabilities or costs associated with non-compliance.

What are the 5 stages of Web Application Pen Testing?

When it comes to web application pentest methodology, different testers may follow different approaches. This strategy is also subject to change depending on the nature of business, existing assets, its state, and the objective of the exercise.

However, the following five stages cover all grounds for web app pen testing strategy:

1- Scope

Pen testing follows a highly focused approach, so pen testers often kick off the project by clearly defining the scope. 

In this respect, a scope is the sum of all the boundaries involved in the engagement. Typically, these boundaries would be a combination of all items that are to be tested. In contrast, the scope may also list out the exclusions for the engagement, which would surround the system, software, network, or activity, which is beyond the purview of pen testing for the said engagement. As such, it lays the groundwork for all the planning involved in carrying out effective pen-testing.

Having a well-defined, granular, and focused scope allows businesses to extract more value from the pen testing exercise and ensures that the process is cost-efficient. 

2- Reconnaissance and Planning

The next stage of web app pen testing is reconnaissance

As the name indicates, reconnaissance involves web application information gathering

It is singularly the most critical phase of penetration testing as the tester views the application through the eyes of a hacker. And in this pursuit, the more intelligence they have on the application, the more effective and holistic their approach to securing all vulnerabilities would be. Testers will scan everything – from the business website to the social media handles – to map out the entire application network and understand the various technologies and protocols employed.

3- Vulnerability Discovery

Once the complete layout of the application infrastructure is ready, it is time to check out its response to security threats and attempts at intrusion. To facilitate this action, packets of data are sent to the target application, and the corresponding response is interpreted. The tester may discover security oversights through this approach, such as open listening ports, integration points, operating system information, internet gateways, IP addresses, installed services, backdoors, and more.

Based on these discoveries, the tester will prepare a vulnerability assessment report.

4- Penetration and Exploitation

The intelligence gathered in the previous two stages is put together to attack the target application at this stage. The tester will deploy a mix of web application attacks, such as the ones discussed above, to target vulnerabilities and exploit them. As such, they could attempt to escalate privileges, steal data, intercept traffic, upload scripts, etc., to measure the impact and damage caused by the attack.

Further, the tester will also check whether the vulnerability can be exploited only as a one-time measure or is a persistent issue that offers long-term and in-depth access. Such consideration will factor in advanced and persistent threats that could potentially make a home in the application and capitalize on the opportunity to compromise data when the opportunity strikes.

5- Analysis and Reporting

Finally, all the observations and insights captured in the above stages are compiled into a detailed report that captures:

  • The vulnerabilities present in the application.
  • How these vulnerabilities can be exploited.
  • The damage and threat to sensitive and accessible data.
  • The degree to which such information could be extracted.
  • The period until which the vulnerability could be exploited.

These inputs will empower developers to undertake the necessary precautions and security measures to fix all vulnerabilities. Businesses must also set in place a retesting schedule that will conduct routine pen testing on assets after every remediation cycle.

What are the Web Application Pen Testing Standards?

Web application pentest methodology can follow any of the following standards:

OWASP (Open Web Application Security Project) 


Security experts highly recommend the OWASP methodology of pen testing because it is structured. The application testing guide covers web and mobile applications and firmware.

OSSTMM (Open Source Security Testing Methodology Manual) 


OSSTMM is a trusted peer-reviewed strategy that has become an industry standard. It played a pivotal role in the foundation for modern-day cybersecurity. Presently, it serves as a reference for several businesses that aim to conduct quality, efficient, and organized pen-testing.

ISSAF (Information Systems Security Assessment Framework) 


ISSAF compiles data against what is known as the ‘evaluation criteria.’ Each of these criteria is designed and reviewed by experts from time to time. This methodology is supported by the Open Information Systems Security Group (OISSG).

PCI DSS (Payment Card Industry Data Security Standard)


PCI DSS is the leading security standard formalized by various credit and debit card companies to safeguard digital transactions. It mandates multiple requirements that businesses must follow to accept payments.

PCI Requirement 11.3 clearly defines vulnerability scans and penetration tests

PTF (Penetration Testing Framework) 

PTF outlines a comprehensive guide for penetration testing. It deploys an array of security tools for the various stages of pen-testing.

What can organizations do to protect web apps and their customers?

In order to protect sensitive information, your company may want to think about implementing the following web application security precautions:

Shift ‘Left’ to the SDLC

Custom web applications allow organizations to provide their customers with the ability to interact with your business through a tailored platform to their needs.

To prevent applications from putting your organization and your customers at risk, it’s critical to be knowledgeable about the security protocols during the development phase of apps.

Independent developers handling passwords in their apps are like a circus performer balancing on a tightrope. Sooner or later, they will come crashing back down to earth. 

One of the biggest mistakes we’ve seen these folks make while passing between two points is not adding encryption security to protect stored passwords.

Regularly perform vulnerability assessments

One of the best ways to protect your web application is by conducting penetration testing regularly. A penetration testing has several benefits like determining whether your current security arrangements are strong enough or they could be further improved, letting you understand how vulnerabilities could be exploited on your web application.

Without regular verification and routine checks, one can never be too sure if the system remains secure or not.

Patch management

As an enterprise architect, it is important that you oversee the security and upkeep for both your proprietary and open source web applications


Conducting a pen test is just the first stage of a multi-layered strategy centered around security. The real crux of the activity rests in identifying threats and devising a roadmap for maintaining data sanctity. During and after conducting pen tests, dedicate the time and resources to analyze, discuss, and truly understand business requirements with respect to security. Then, check how the current measures align with the organizational objectives.

Carry out the required correction and repeat the process once again after some time. In this way, businesses will soon have a robust IT infrastructure in place that is subject to periodic review and all set to take the company to new heights.

Scroll to Top