Web application penetration testing: tools, methodology and best practices

WHAT IS WEB APPLICATION PENETRATION TESTING?

WHY DO YOU NEED TO PERFORM WEB APPLICATION PENETRATION TESTING?

Web application penetration testing is a critical security step for any organization that hosts or manages web applications. Web applications are a prime target for cyber criminals because of their growing usage, accessibility, and often lack of security controls. Recent statistics show that 98% of web applications are vulnerable to cyber attacks that can result in malware, redirection to malicious websites, and more. Moreover, 72% of these vulnerabilities were due to flaws in the application code itself. 

A major reason for these vulnerabilities is that the development process does not include application security in the early stages of the development cycle. The result is that organizations often only identify and fix these flaws at the end of the development process, when it is costly, time-consuming, and late. The benefit of continuously testing web applications throughout the development cycle is that security is built in and becomes part of the application itself, letting you fix vulnerabilities as you build the application. 

Web application pen tests help to ensure that there are no existing vulnerabilities or weak points in the system that could potentially be exploited by malicious actors. It provides an in-depth analysis of the web application, from user interface to codebase, to identify any security vulnerabilities that may exist. By conducting a thorough review of the web application and its architecture, the pen tester can identify the weak points and address the potential gaps that could be used to break into the system. This includes hardware, software, policies, procedures, and people. 

In addition, pen tests can detect any breaches of data that may have already existed and gone unnoticed for a long time. For instance, The Equifax breach is a perfect example of a vulnerability that went undetected for many months and could have been prevented with regular security checks. Such incidents highlight the importance of web application pen tests in detecting underlying vulnerabilities that could result in a data breach. 

Web application pen testing also has numerous other benefits. It can help you stay compliant with relevant industry standards and regulations. For example, the PCI-DSS pen testing process is designed to test all aspects of the cardholder data environment to identify vulnerabilities in the system.

Other than compliance and security, pen tests can be a useful tool in evaluating the performance of your web application, assure your customers that you have a secure system, and reduce the cost of support and maintenance of your web application.

Since there are different web applications and each demands unique testing style, therefore testing is carried out from a list of widely accepted methodologies. Typically, a web application penetration testing methodology involves:

• Information gathering – information concerning the web architecture, information leakage, web service integration, and other associated information to give the tester a guide
• Installation of tools for experimentation. Examples of such tools include: N-Stalker, Sand Cat;
• Understanding firewalls and other security protocols.
• Platform testing and configuration
• Error handling and data validation testing
• Encryption related protection testing
• Client-side and business logic testing.
• Tests report generation and remedies suggestion
• Vulnerabilities retest and cleanup

Typically, a comprehensive Web Application Penetration Testing methodology involves four main steps that focus on the various elements of a web application. These include Information Gathering, Vulnerability Testing, Exploitation, Risk Assessment, and Reporting. 

Information Gathering is the first step in the process and involves collecting as much information as possible about the target web application as well as its associated network, systems, and applications to identify any potential security vulnerabilities that may exist. This information includes the URL, valid credentials, roles, and any other valid test data. 

Vulnerability testing is the second step in the process and involves the actual testing of the application to identify vulnerabilities, security flaws, and technical errors. The goal is to find the security weaknesses in the application and suggest the apprised solutions to fix them.

The following is a full list of areas that must be tested for a given web application:

• Authentication Testing

• Authorization Testing

• Session Management Testing

• Input Validation Testing

• Cryptography

• Configuration and Deployment Management Testing

• Identity Management Testing

• Error Handling

• Business Logic Testing

• Client Side Testing

Next comes Risk Assessment, which is the process of assessing the impact of a given vulnerability on the target web application, when successfully exploited. Once a vulnerability is identified, the next step is to prioritize the vulnerabilities according to the likelihood of being exploited. Then, the impact of exploitation is estimated based on the consequences of exploitation. Finally, the risks are assessed and ranked to determine the severity of the vulnerability. 

Reporting is the final stage of the testing process. This stage entails the reporting of the results of the testing process, which include a summary of the vulnerabilities found, details of the testing process, and the steps to remediate the vulnerabilities. 

Source: Infosec Institute

To be certain about the validity of testing methodologies, such method could be compared with some other testing methodology benchmark such as; Penetration Testing Framework (PTF), Open Web Application Security Project (OWASP), or Information Systems Security Assessment Framework (ISSAF). 
With all the processes put to use and they do not perform below the testing methodology benchmark such as examples given above, you can be confident of the safety of your web application. Web application penetration testing methodology can be mitigated by security professionals by detecting any concerns and highlighting any weaknesses inside your sites.

As stated earlier, there are many web application penetration testing tools, but the validity of a testing tool depends on the type of task it is meant for. Listed below are some open source web application penetration testing tools:

• Zed Attack Proxy (ZAP)
• Wfuzz
• Wapiti
• W3af
• SQLMap

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