SEC542: Web App Penetration Testing and Ethical Hacking

Overview

Understanding the attacker's perspective is key to successful web application penetration testing. The course begins by thoroughly examining foundational concepts such as web technology, including protocols, languages, clients, and server architectures, from the attacker's perspective. We look at collecting open-source intelligence (OSINT) specific to data points likely to help exploitation be more successful, and we analyze the importance of encryption and HTTPS.

We look at the methodology promoted by OWASP to help ensure the delivery of high-quality assessments, as well as the things necessary for a penetration testers toolkit. The most important tool, an interception proxy, is introduced through performing the initial configuration steps in OWASPs Zed Attack Proxy (ZAP) and BurpSuite Professional, the latter being a tool we use further to explore aspects of a vulnerable web application.

Section one concludes with profiling the target(s) to understand the underlying configuration. The collected data is used to build a profile of each server and identify potential configuration flaws. The discussion is underscored through several practical, hands-on labs in which we conduct reconnaissance in order to find forgotten virtual hosts. Students will get deeper hands-on experience with BurpSuite Pro, cURL, and manual exploitation techniques with tools such as nmap and testssl.sh.

Topics

• Overview of the web from a penetration tester's perspective
• Web application assessment methodologies
• The penetration tester's toolkit
• Interception proxies
• Proxying SSL through BurpSuite Pro and Zed Attack Proxy
• DNS reconnaissance
• Virtual host discovery
• Open-source intelligence (OSINT)
• The HTTP protocol
• Secure Sockets Layer (SSL) configurations and weaknesses
• Target discovery and profiling

• Configuration flaws

Overview

Modern web applications frequently are not monitored as closely as they should, giving attackers the opportunity to discover, and exploit, vulnerabilities without anyone noticing. A systems configuration should involve proper logging and monitoring to ensure security-related events are not missed. That is why in this section we briefly explore logging configuration and basic incident response testing.

We enumerate the application's pages and features. This phase involves identifying the components, analyzing the relationship between them, and determining how the pieces work together. We then dive deep into the spidering/crawling results, which represents a vital part of the overall penetration test, as well as perform forced browsing to find hidden content in a lab. This lab also introduces an extremely fast fuzzer, ffuf.

We examine different authentication systems, including Basic, Digest, Forms, Windows Integrated and OAuth authentication, and discuss how servers use them and attackers abuse them. We perform username enumeration and use Burps fuzzer, Intruder, to guess the password used to successfully authenticate to a web application. We gain hands-on experience with Burp sequencer. Then we end with a discussion of authentication and authorization bypasses, which can expose sensitive data and business functions to attackers, as well as exploit an authentication flaw in Mutillidae.

Topics

• Logging and monitoring
• Learning tools to spider a website
• Analyzing website content
• Brute forcing unlinked files and directories via ZAP and ffuf
• Web authentication mechanisms
• Fuzzing with Burp Intruder
• Username harvesting and password guessing
• Burp sequencer
• Session management and attacks
• Authentication and authorization bypass
• Mutillidae

Overview

After ending section two with authentication bypass, we begin section three by exploring security-related protections included in the web servers responses: cookie flags and response headers.

We build on the information identified during the target profiling, spidering, and forced browsing exercises, exploring methods to find and verify vulnerabilities within the application. Students also begin to explore the interactions between the various vulnerabilities.

This course section dives deeply into vital manual testing techniques for vulnerability discovery. We focus on developing in-depth knowledge of interception proxies for web application vulnerability discovery. Many of the most common injection flaws (command injection and local and remote file inclusion) are introduced, and followed with lab exercises, to reinforce the discovery and exploitation.

Besides this, a section covers insecure deserialization, a common vulnerability in object-oriented programming languages, where students will exploit a Java insecure deserialization vulnerability in a lab to steal a secret file from a vulnerable web application. This lab requires more effort and demonstrates chaining of vulnerabilities to achieve the final goal.

Due to its prevalence and the significant impact generally associated with the flaw, a considerable portion of this section is devoted to traditional and blind SQL injection.

Topics

• HTTP resonse security controls
• Command injection
• Directory traversal
• Local File Inclusion (LFI)
• Remote File Inclusion (RFI)
• Insecure deserialization
• SQL injection
• Blind SQL injection
• Error-based SQL injection
• Exploiting SQL injection
• SQL injection tools: sqlmap

Overview

Section four continues exploring injection flaws and spends time introducing Cross-Site Scripting (XSS) vulnerabilities, including reflected, stored, and DOM-based XSS vulnerabilities. Manual discovery methods are employed during hands-on labs, and students are introduced to the developer tools in browsers, as a means of analyzing client side JavaScript in modern web applications.

Section four also introduces the Browser Exploitation Framework (BeEF) to students, which is used in multiple labs. The course continues with a detailed discussion of AJAX as we explore how it enlarges the attack surface leveraged by penetration testers. We also analyze how AJAX is affected by other vulnerabilities already covered in depth earlier in the course.

We discuss REST (Representational State Transfer) and SOAP (Simple Object Access Protocol). Finally, section four ends with us covering server-side request forgery (SSRF) and XML external entities (XXE)both of which include an associated lab. Again, in the SSRF lab multiple vulnerabilities are chained, relying on previously covered material.

Topics

• Cross-Site Scripting (XSS)
• Browser Exploitation Framework (BeEF)
• AJAX
• XML and JSON
• Document Object Model (DOM)
• API attacks
• Data attacks
• REST and SOAP
• Server-Side Request Forgery (SSRF)
• XML Eternal Entity (XXE)

Overview

During the fifth section, we launch actual exploits against real-world applications, expand our foothold within the application, and extend it to the network on which it resides. As penetration testers, we specifically focus on ways to leverage previously discovered vulnerabilities to gain further access, highlighting the cyclical nature of web application penetration testing.

During our exploitation phase, we expand our use of tools such as ZAP and BurpSuite Pro, plus complement them with further use of sqlmap and Metasploit to help craft exploits against various web applications. We launch SQL injection and Cross-Site Request Forgery attacks, amongst others. In class we exploit these flaws to perform data theft, hijack sessions, deface a website, get shells, pivot against connected networks, and much more. Through various forms of exploitation, students gain a keen understanding of the potential business impact of these flaws to an organization.

Students are also introduced to Nuclei  a modern, open-source vulnerability scanner tool that is very popular among bug bounty hackers  in a lab that combines usage of Nuclei and Metasploit.

While the whole course is geared toward understanding how web application vulnerabilities work and how they can be exploited, we also discuss the active scanner component in BurpSuite Pro.

To position students to take their skills to the next level, the last lab of section five looks at an instance where a Metasploit module fails to exploit a vulnerability that has been confirmed to exist in the target web application. We explore a process to research the flaw, manually exploit the vulnerability, and then reconfigure the Metasploit module to successfully gain a shell. This exercise gives students necessary skills to dig deeper when automated tools fail.

We wrap up course instruction by reviewing how to prepare for penetration testing assessments and important post assessment activities, such as report writing.

Topics

• Cross-Site Request Forgery (CSRF)
• Logic attacks
• Python for web app penetration testing
• WPScan
• ExploitDB
• BurpSuite Pro scanner
• Nuclei
• Metasploit
• When tools fail
• Business of Penetration Testing:
• Preparation
• Post Assessment and Reporting

Overview

During section six, students form teams and compete in a web application penetration testing tournament. This Netwars-powered Capture-the-Flag exercise provides students an opportunity to wield their newly developed or further honed skills to answer questions, complete missions, and exfiltrate data, applying skills gained throughout the course. The style of challenge and integrated hint system allows students of various skill levels to both enjoy a game environment and solidify the skills learned in class.