How to Perform Penetration Testing to Identify System Vulnerabilities

November 26, 20234 min read

Penetration testing, also known as pen testing or ethical hacking, is a simulated cyberattack against your computer system to check for exploitable vulnerabilities. Below are detailed steps on how to perform penetration testing effectively.

Planning and Reconnaissance

Objective Definition:

  • Define the scope and goals of a test, including the systems to be addressed and the testing methods to be used.

Intelligence Gathering:

  • Gather intelligence (e.g., network and domain names, mail servers) to understand how a target works and its potential vulnerabilities.


Static Analysis:

  • Inspect an application’s code to estimate the way it behaves while running. Tools like code analyzers can be used.

Dynamic Analysis:

  • Inspect an application’s code in a running state. This is a more practical way of scanning, as it provides a real-time view into an application’s performance.

Use of Tools:

  • Use tools such as Nmap for network mapping and port scanning.
  • Nessus or OpenVAS can be used for vulnerability scanning to discover known vulnerabilities.

Gaining Access


  • Use web application attacks, such as cross-site scripting, SQL injection, and backdoors to uncover a system’s vulnerabilities.

Exploit Tools:

  • Metasploit, Burp Suite, and other similar tools can be used for exploiting vulnerabilities.


  • Document the vulnerabilities exploited, the data accessed, and how long you remained undetected in the system.

Maintaining Access

Establishing Persistence:

  • Ensure that the backdoor remains open for future attacks and assessments.

Data Exfiltration Simulation:

  • Test data exfiltration to determine how data can be stolen and how much data can be exfiltrated without being detected.


Compile Results:

  • Gather the data from the penetration test and analyze it to assess the impact of the vulnerabilities.


  • Create a detailed report containing:
    • Specific vulnerabilities that were exploited
    • Sensitive data that was accessed
    • The amount of time the pen tester was able to remain in the system undetected.


  • Provide recommendations for security improvements to protect against real attacks.



  • Remove all tools, scripts, and data files placed in the target system during the penetration testing.


  • Verify that the vulnerabilities have been patched and the recommendations implemented.


  • Optionally, perform a retest to ensure all vulnerabilities have been successfully mitigated.

Tools and Resources

Penetration Testing Tools:

  • Some standard tools include:
    • Scanners: Nmap, Nessus, Nikto, Wireshark
    • Exploit frameworks: Metasploit
    • Password cracking: John the Ripper, Hashcat
    • Web application testing: Burp Suite, OWASP ZAP
    • Wireless Testing: Aircrack-ng, Kismet

Training and Ethical Considerations:

  • Pen testers should be trained and certified (e.g., OSCP, CEH).
  • Obtain proper authorization before beginning a pen test to ensure legality and ethics.


  • Use a standardized reporting format to ensure that the findings are documented in a consistent and comprehensive manner.

By strategically following these phases and implementing the required tools and methodologies, you will be able to uncover and prioritize the resolution of system vulnerabilities, thereby enhancing the overall security posture of the infrastructure you are testing. Remember that the goal is not only to find vulnerabilities but also to provide actionable insights and recommendations to improve the system’s security.