Penetration testing

Penetration testing (a pentest) is a controlled and authorized simulation of an attack on a system, application or network, aimed at finding and practically exploiting security flaws. Unlike automated scanning, a pentest involves the manual, creative work of a specialist who thinks like a real attacker and combines individual weaknesses into complete intrusion scenarios.

How a penetration test works

A pentest proceeds in stages. It starts with reconnaissance (gathering information about the target), followed by scanning and mapping the attack surface, after which the tester moves to exploitation — attempting to abuse the vulnerabilities found, such as SQL injection, XSS or broken access control. Once inside, the tester assesses how deep the intrusion can go (privilege escalation, lateral movement across the network), and the engagement ends with a report listing vulnerabilities, risk ratings and remediation advice. Depending on prior knowledge, three variants exist: black box (the tester knows nothing about the system internals), white box (full documentation and source code) and grey box (partial knowledge). The work is structured by standards such as the OWASP Testing Guide or PTES.

Practical application

Penetration tests are commissioned by banks, online stores and companies processing personal data to verify system resilience ahead of an audit or compliance review. They reveal vulnerabilities that are invisible in code and in firewall configuration until someone actually tries to abuse them with a working exploit. A pentest is always carried out under a written agreement that defines the scope and boundaries — testing someone else's system without permission is a crime. Regular pentests are often complemented by bug bounty programs, where independent researchers are rewarded for the flaws they report.