How do you perform a penetration test on a web application?

Scoping a penetration test isn't just about boundaries; it's about aligning expectations. Engaging stakeholders early ensures a shared understanding of the test's purpose, risk tolerance, and desired outcomes. This collaboration fosters transparency, mitigates misunderstandings, and ensures that the findings are actionable and relevant to the organization's security posture.

Two of the primary things you want to do before conducting a penetration test are 1.) creating a scope of the test - describing what must be done and 2.) creating a Rules of Engagement - outlining how these things must be done. By doing these, you ensure that you - as the tester - and the client, are on the same page. When scoping a web-application, there are many factors you want to consider. These include, but are not limited to: the number of login systems, dynamic pages, and static pages being tested; whether role-based testing, fuzzing, and static analysis will be done; how much of the source code will be available for viewing, and more.

Perform web application penetration testing by identifying attack vectors, including SQL injection, cross-site scripting, and authentication bypass. Utilize tools like Burp Suite or OWASP ZAP for vulnerability scanning. Exploit vulnerabilities, escalate privileges, and document findings. Provide actionable recommendations for remediation and retest for validation.

On top of the tools mentioned, explore other tools and methods to find vulnerabilitys. For web based vulnerabilities there is many tools that can automate the job. Such as SQLMap and Nikito. Make use of Dirbuster, or Gobuster to find hidden directories and subdomains you might not find on intial enumeration. As these could expose more vulns on pages that are not linked. Ensure directories found this way, are within scope of the test, and always be sure you are avoiding scope creep.

In my experience, thorough reconnaissance and mapping lay the groundwork for a successful web application penetration test. For instance, during a recent engagement, we utilized a combination of tools and techniques to gather intelligence about the target web application. By conducting DNS lookups, WHOIS queries, and network scans, we were able to identify the web app's infrastructure and dependencies, including its hosting provider, IP address, and underlying technologies. Additionally, by meticulously mapping the web app's structure and functionalities, we uncovered potential attack vectors, such as input fields and URLs, which informed our subsequent testing strategy.

While performing reconnaissance of the target you have to ensure you stay within scope. While gathering OSINT, and adding subdomains, email addresses, databases, ect to your pool is important there is cases where certain aspects may be beyond the scope for the engagement. An example could be a database that may not be in the test parameters, or a "Dev Subdomain". The scope is important here, as there may be vulnerabilities present they are aware of in these areas and do not want them included in the test. They may not be ready to have that area tested yet, or may be trying to find issues with only certain areas of the target at the time. This is very important to be clear about in scope, and follow that scope during engagement.

1. Passive Reconnaissance: Passive reconnaissance involves gathering information without directly interacting with the target application. Public Information Gathering: 2. Active Reconnaissance: Service Fingerprinting: Identify services on open ports using tools like Nmap Web Application Scanning: Burp Suite to enumerate the web application structure, discover available pages. Mapping:1. Identify Entry Points Input Fields: Locate all input fields, forms, and parameters that accept user input File Uploads: Identify any file upload functionalities, which can be 2. Enumerate Web Application Components APIs: Identify and enumerate all API endpoints exposed by the application. Tools like Postman or Burp Suite can help analyze API requests.

For advanced reconnaissance, consider using tools like Shodan for discovering hosts connected to the internet, theHarvester for gathering emails and subdomains, and SpiderFoot for automating OSINT collection. Also, don’t forget to check GitHub repositories for any leaked sensitive information related to the web app.

Mnaul testing should always be completed, but automated tools can also speed the process of findings and should not be ignored. The majority of breeches are made using low hanging fruit, so odds are high that low hanging fruit is the target of the scope. Things like SQLMap, can speed up the search for vulns. Vulnerability Scanners can also find issues. Also be sure to check for directories that are not immediately apparent on intial access. Using tools like Gobuster and Dirb to find these subdomains, and other directories that might not be linked at first glance. Ensure these are in your scope before testing them however, as they may not be ready for these to be tested.

Vulnerability scanning involves using automated tools to scan the web application for known vulnerabilities. These tools can identify a wide range of security issues and common web application vulnerabilities. 1. Choose the Right Tools: Burp Suite: A comprehensive platform for performing security testing of web applications. Nessus: A vulnerability scanner that can identify a wide range of security issues. 2. Configure the Scanning Tools: Specify the target web application URL(s) to be scanned. 3. Run the Scan: Perform an initial scan to identify obvious and easily detectable vulnerabilities. In-Depth Scan: Conduct a more comprehensive scan that includes 1. Categorize Vulnerabilities: Organize the vulnerabilities based on their severity

While automated tools are great, they can’t replace manual testing. For example, business logic flaws can only be identified through manual testing. Also, consider using source code analysis tools if the source code is available, as they can help in identifying vulnerabilities that might be missed by dynamic analysis tools.

The exploitation phase of a web application penetration test requires a methodical approach and adherence to ethical standards. In a recent engagement, after identifying vulnerabilities such as SQL injection and cross-site scripting, we meticulously crafted payloads and utilized tools like sqlmap and Metasploit to exploit these weaknesses. However, it's crucial to exercise caution and restraint during exploitation, ensuring that actions are conducted within the predefined scope and objectives of the test. By documenting our steps and findings, including screenshots and command outputs, we provided clear evidence of the vulnerabilities' impact while upholding the integrity and confidentiality of the target web application.

Prepare for Exploitation: Gather Information: Collect detailed information about the identified vulnerabilities, including potential attack vectors and exploit techniques. Set Up Environment: Ensure you have a controlled environment or proper authorization to perform exploitation to avoid unintended consequences. 1. Confirm Vulnerability: Repeat Exploitation: Verify the vulnerability by repeating the exploitation steps to ensure consistent results. Cross-Validation: Use multiple tools or methods to cross-validate the exploitation findings. 2. Assess Impact: Access Level: Determine the level of access gained through exploitation (e.g., user account, administrator access). Data Compromised: Identify the type and amount of data compromised.

When exploiting vulnerabilities, it’s crucial to understand the impact on the business, not just the technical impact. For example, a vulnerability that allows an attacker to bypass the shopping cart process might have a significant business impact. Also, consider using a proxy tool like Burp Suite to modify and replay HTTP requests, which can be very useful in exploitation and verification.

Reporting is the billable aspect of any pentration test. The vulnerabilities need to be corrected, this happens from your report. In addition to rating by CVSS scores, and the like. Also if able you should be suggesting fixing the vulnerabilities so that they can repair them. Be sure to only speak to what you know, and facts as best as possible. As you do not want to give bad advice, however if you are aware of a fix for the vuln, or have suggestions you should share them. As the ultimate goal is to not only find, but to fix the vulnerabilities.

1. Executive Summary: Purpose: Provide a high-level overview of the penetration test, including objectives, scope, and key findings. Audience: Tailor this section for non-technical stakeholders, such as executives and management. Content: Summarize the overall security posture, major vulnerabilities found, and their potential business impact. 2. Methodology: Testing Approach: Describe the penetration testing methodology used, including tools, techniques, and procedures. Scope: Outline the scope of the test, specifying the web application components, pages, and functionalities tested. Limitations: Mention any limitations or constraints faced during the testing process. 1. Plan Remediation: Assign Responsibility: Designate responsible teams

In the report, it’s important to explain the root cause of each vulnerability and provide detailed remediation steps. Also, consider providing a risk rating for each vulnerability based on a standard like CVSS. After delivering the report, offer to assist in the remediation process and provide a re-testing service to ensure the vulnerabilities have been properly fixed.

One aspect worth considering is the importance of continuous improvement and knowledge sharing in the field of web application penetration testing. As technology evolves and new vulnerabilities emerge, staying abreast of the latest tools, techniques, and attack vectors is imperative for penetration testers. Engaging in ongoing training, participating in Capture The Flag (CTF) competitions, and contributing to open-source projects are excellent ways to hone one's skills and expand one's expertise in web application security testing. Additionally, fostering collaboration and information exchange within the cybersecurity community fosters a culture of learning and innovation, ultimately benefiting all stakeholders involved.

While testing the Web Vulnerabilities, be sure to test the enviroment from which they are sourced. Apache servers, ISS servers, CMS platforms like Wordpress. These have frequently vulns for themselves, that can translate to the Web asset. Be sure to not limit results of not looking for these, as they could hold major issues that need to be addressed.

Penetration testing is a continuous process. Regularly scheduled tests are important as new vulnerabilities can be introduced over time. Also, consider implementing a bug bounty program. This can help in discovering vulnerabilities that might be missed during the penetration test, as it allows a diverse group of researchers to examine the application.