The Basics of Hacking and Penetration Testing

1. Ethical Hacking: A Force for Good

In nearly every situation, an ethical hacker should strive to act and think like a real black hat hacker.

Authorization, Motivation, and Intent. Ethical hacking, or penetration testing, is a legal and authorized attempt to find and exploit vulnerabilities in computer systems to improve their security. The key differences between ethical ("white hat") and malicious ("black hat") hackers lie in authorization, motivation, and intent. White hats always have permission, are motivated by a desire to improve security, and intend to help the organization.

Penetration Testing vs. Vulnerability Assessment. While vulnerability assessments identify potential security issues, penetration tests go further by simulating real-world attacks to prove the existence of vulnerabilities. This involves actively exploiting systems and demonstrating the impact of security flaws.

White Box vs. Black Box Testing. White box testing is thorough and comprehensive, examining every aspect of a system, while black box testing simulates a real-world attack, focusing on stealth and precision. Both approaches have value, depending on the goals of the penetration test.

2. Reconnaissance: The Art of Digital Investigation

The more time you spend collecting information on your target, the more likely you are to be successful in the later phases.

Information Gathering is Key. Reconnaissance, or information gathering, is the most important phase of a penetration test, often overlooked by beginners. It involves collecting as much information as possible about the target, both actively (interacting directly with the target) and passively (using publicly available information).

Tools and Techniques. Reconnaissance utilizes a variety of tools and techniques, including website copiers (HTTrack), search engine directives (Google-Fu), email address harvesters (The Harvester), WHOIS lookups, DNS interrogation tools (host, dig, fierce), and metadata extraction tools (MetaGooFil). Social engineering also plays a crucial role in gathering information.

Cyclical Process. Reconnaissance is a cyclical process, as new information often leads to the discovery of new targets, requiring further investigation. The goal is to create a list of attackable IP addresses or URLs, while respecting the scope of the test.

3. Scanning: Mapping the Digital Terrain

You need to understand more than just how to simply run the security tools in this book. Understanding the proper sequence in which they are run is vital to performing a comprehensive and realistic penetration test.

From IPs to Open Ports. Scanning involves identifying live systems and the services running on those systems. This phase is broken down into ping sweeps (FPing), port scanning (Nmap), and vulnerability scanning (Nessus).

Nmap: The Port Scanner. Nmap is a versatile tool for port scanning, capable of performing TCP connect scans, SYN scans, UDP scans, and Xmas scans. Understanding the differences between these scan types is crucial for effective port scanning. The Nmap Scripting Engine (NSE) extends Nmap's functionality, allowing for more advanced interrogation and vulnerability detection.

Vulnerability Scanning with Nessus. Nessus is a vulnerability scanner that identifies known weaknesses in software and services. It goes beyond port scanning by actively checking for specific vulnerabilities, providing a list of potential exploits.

4. Exploitation: Turning Weaknesses into Access

The ultimate goal of exploitation is to have administrative access (complete control) over the target machine.

Exploits and Payloads. Exploitation is the process of gaining control over a system by leveraging vulnerabilities. This involves using exploits (code that takes advantage of a vulnerability) to deliver payloads (code that performs a specific action on the target).

Online Password Cracking. Tools like Medusa are used to brute-force login credentials for remote services like SSH and Telnet. This involves trying various username and password combinations until a successful login is achieved.

Metasploit: The Exploitation Framework. Metasploit is a powerful framework that simplifies the process of exploitation. It provides a vast library of exploits and payloads, allowing for rapid and efficient attacks. Understanding the difference between bind and reverse payloads is crucial for successful exploitation.

5. Social Engineering: Hacking the Human Element

Social engineering is the process of exploiting the “human” weakness that is inherent in every organization.

Exploiting Human Trust. Social engineering is the art of manipulating people into divulging confidential information or performing actions that compromise security. It often involves creating believable scenarios and pretexts to gain the trust of the target.

The Social-Engineer Toolkit (SET). SET is a framework that automates many social engineering techniques, including website cloning, credential harvesting, and malicious USB drive creation. It allows for the rapid deployment of sophisticated attacks.

Believability is Key. Successful social engineering attacks rely on believability. The more realistic and plausible the attack vector, the more likely it is to succeed. This often involves tailoring the attack to the specific target and their environment.

6. Web-Based Exploitation: Targeting the Internet's Core

In many ways, the Internet is like the new “wild west”.

The Web as an Attack Vector. Web-based exploitation targets vulnerabilities in web applications and servers. This involves using tools like Nikto, w3af, and WebScarab to identify and exploit weaknesses.

Intercepting Proxies. Intercepting proxies like WebScarab allow for the manipulation of HTTP requests and responses, enabling the discovery of hidden fields and vulnerabilities. This involves setting up a proxy server and routing all web traffic through it.

Code Injection and XSS. SQL injection and cross-site scripting (XSS) are common web-based attacks. SQL injection involves manipulating database queries to gain unauthorized access, while XSS involves injecting malicious scripts into web pages to target users.

7. Post-Exploitation: Maintaining Control and Covering Tracks

Persistent reusable backdoors on systems are a malicious attacker’s best friend.

Backdoors for Persistent Access. Backdoors are used to maintain access to a compromised system after the initial exploit. This often involves installing software that allows for remote access and control.

Netcat: The Swiss Army Knife. Netcat is a versatile tool for creating backdoors, transferring files, and establishing communication channels. Cryptcat provides similar functionality with the added benefit of encryption.

Rootkits: Hiding in the Shadows. Rootkits are used to hide files, processes, and services from the operating system, making them difficult to detect. Hacker Defender is a Windows rootkit that can be used to demonstrate this technique.

8. The Penetration Testing Report: Communicating Value

The final PT report should include all the relevant information uncovered in your test and explain in detail how the test was conducted and what was done during the test.

The Importance of the Report. The penetration testing report is a crucial deliverable that summarizes the findings of the test. It should be well-organized, easy to understand, and provide specific recommendations for addressing the discovered vulnerabilities.

Key Components of a Report. A good report includes an executive summary, a detailed description of the testing process, a list of vulnerabilities discovered, and specific recommendations for remediation. It should be readable by both technical and non-technical personnel.

Beyond the Technical Details. The report is often the only tangible evidence that a client receives from the penetration tester. It is an opportunity to showcase your skills and demonstrate the value of the penetration testing process.

Last updated: February 2, 2025