What is penetration testing?

Purpose and importance of pentests

The main purpose of penetration testing is to practically verify the effectiveness of implemented security mechanisms and identify viable attack paths that could be used to compromise a system. Pentests provide an organization with valuable information about the state of its security, allow it to assess the potential impact of a successful attack and identify specific areas for improvement. They are an important component of IT security risk management strategies and often a requirement under compliance standards (e.g. PCI DSS).

Types of penetration tests

Pentests can be classified based on various criteria, including the tester’s level of knowledge of the system under test:

• Black-box testing: Pentester has no prior knowledge of the internal structure or source code of the system under test. It simulates an attack carried out by an external hacker.
• White-box testing: Pentester has full access to system information, including source code, architectural documentation and configuration. This allows for in-depth analysis and identification of more complex vulnerabilities.
• Gray-box testing: The pentester has partial knowledge of the system, such as the login credentials of a regular user. This is an intermediate scenario, simulating an attack carried out by a person with limited access (e.g., employee, customer).

Pentests can also be divided by the purpose of the attack (e.g., external network, internal network, web application, mobile application, social engineering tests).

Stages of conducting a penetration test

A typical penetration test process involves several steps:

• Planning and reconnaissance: Agreeing the scope, objectives and rules of the test with the client. Gathering information about the target of the attack (e.g., port scanning, analysis of publicly available information).
• Vulnerability scanning and analysis: Using automated tools and manual techniques to identify potential vulnerabilities, open ports, out-of-date software or configuration errors.
• Exploitation (intrusion attempt): An attempt to actively exploit identified vulnerabilities to gain unauthorized access to a system, escalate privileges, or perform other malicious activities.
• Post-exploitation analysis (post-exploitation): After gaining access, the pentester assesses what further actions are possible (e.g., accessing sensitive data, taking control of other systems).
• Reporting: Prepare a detailed report for the client, including a description of the vulnerabilities found, an assessment of their criticality, proof-of-concept, and recommendations for remediation and security enhancements.
• Retest (optional): After the customer has implemented the fixes, the pentester can conduct a retest to verify the effectiveness of the countermeasures applied.

Tools used by pentesters

Pentesters use a wide range of tools, both commercial and open-source, including port scanners (e.g., Nmap), vulnerability scanners (e.g., Nessus, OpenVAS), exploitation frameworks (e.g., Metasploit), web application testing tools (e.g., Burp Suite, OWASP ZAP) and proprietary scripts and techniques.

Limitations of pentests

Keep in mind that penetration testing is limited in time and scope. They do not guarantee finding all existing vulnerabilities. They are a snapshot of the state of security at a given point in time and should be conducted regularly and supplemented with other security activities, such as vulnerability management or monitoring.

Summary

Penetration testing is a key tool for proactively assessing the security of IT systems. By simulating real-world attacks, they allow organizations to identify and fix critical security vulnerabilities before they can be exploited by cybercriminals, significantly increasing the level of protection for a company’s information assets.