What actually happens during a professional penetration test from day one to final report?

The engagement begins before any hacking starts

A professional penetration test does not begin with someone hammering away at your firewall. It starts with a scoping call, a rules of engagement document, and a clear understanding of what is and isn't in scope. This preparatory phase is often the most important part of the entire engagement.

During scoping, the testing team will work with your stakeholders to identify critical assets, agree on testing windows, and establish communication channels. Emergency contacts are exchanged, and both sides align on objectives — whether that's compliance validation, threat simulation, or a deep technical assessment.

Without proper scoping, even the most skilled tester risks wasting time on irrelevant targets or, worse, disrupting live business systems. The best engagements are built on transparency and mutual understanding from the outset.

Mapping the attack surface

Once the engagement is formally kicked off, testers begin with passive and active reconnaissance. This involves gathering publicly available information about your organisation — DNS records, email addresses, technology stacks, employee names — and using it to build a picture of your external attack surface.

Active reconnaissance then moves into port scanning, service enumeration, and fingerprinting. The goal is to understand exactly what is exposed, what versions are running, and where the most promising entry points might be. This phase mirrors what a real attacker would do before launching an assault.

Good reconnaissance is methodical and thorough. Testers document every finding, even those that seem insignificant, because low-severity issues often chain together to create critical attack paths later in the engagement.

Attempting to breach defences

With a detailed map of the attack surface, testers begin attempting exploitation. This might involve exploiting known vulnerabilities in outdated software, testing for weak credentials, attempting SQL injection against web applications, or crafting phishing emails if social engineering is in scope.

Each successful exploitation is carefully documented with screenshots, command output, and reproduction steps. Testers aim to demonstrate real-world impact — not just that a vulnerability exists, but what an attacker could actually achieve by exploiting it. This often involves pivoting deeper into the network to reach sensitive data or critical systems.

Throughout this phase, testers maintain constant awareness of their impact on live systems. If something unexpected occurs, they pause, assess, and communicate with the client immediately. Safety and professionalism are non-negotiable.

Turning findings into actionable intelligence

The report is arguably the most valuable deliverable of the entire engagement. A high-quality penetration test report includes an executive summary for leadership, detailed technical findings for remediation teams, and clear evidence supporting every claim.

Each finding is rated by severity and accompanied by specific, actionable remediation guidance. The best reports don't just say 'patch this' — they explain the business risk, the attack scenario, and the steps needed to close the gap permanently.

After delivery, a professional testing firm will offer a debrief session to walk stakeholders through the findings, answer questions, and help prioritise remediation efforts. Many firms also offer free retesting to verify that fixes have been implemented correctly.

A structured process, not a free-for-all

A professional penetration test follows a disciplined, repeatable methodology from scoping through to retesting. Understanding what happens at each stage helps organisations get maximum value from their investment and build a stronger security posture over time.