A penetration test is a controlled attack simulation
A penetration test (pentest) consists of simulating, within a defined legal and contractual framework, the techniques a real attacker could use against an information system, an application or a network. The goal is not to "hack for the sake of hacking," but to identify exploitable vulnerabilities before a malicious actor does, then document them in enough detail so technical teams can fix them effectively. Unlike an automated vulnerability scan, a pentest involves manual expert work that seeks to chain several flaws together, sometimes minor when taken individually, to assess real-world impact on the organization — not merely produce a list of theoretical findings ranked by a generic severity score. It is this human, creative dimension, mirroring how a real attacker operates, that fundamentally distinguishes a pentest from a simple automated check. It is worth noting that a pentest always takes place within a strict contractual framework, with prior written authorization that precisely defines what is permitted — without this framework, the same actions would constitute an illegal intrusion rather than a legitimate security exercise. This written authorization protects both the commissioning company and the team conducting the test, and is a non-negotiable prerequisite for any serious engagement.
The main categories of pentest
Web pentest: applications and sites accessible online, looking for flaws such as injections, authentication or access control issues, and session management weaknesses. Mobile pentest: iOS and Android applications, local data storage on the device, communication with servers, security of mobile-specific authentication mechanisms. Network and infrastructure pentest: network devices, servers, segmentation between environments, remote access configuration. Cloud pentest: AWS, Azure or GCP environments, with particular attention paid to identity and access management (IAM) configuration, often the most critical weak point in these environments. Some engagements combine several of these scopes depending on the organization's specific concerns, for example when a web application relies on cloud infrastructure and communicates with an associated mobile app. The choice of scope depends directly on what represents the most value or the most risk for the organization: an e-commerce business will often prioritize its web application and payment infrastructure, while an industrial company will pay closer attention to its internal network and control systems.
How an engagement unfolds, step by step
A pentest engagement generally follows a structured process. First, a precise scoping of the perimeter and rules of engagement: systems involved, authorized testing windows, emergency contacts in case of unexpected impact on production. Next comes a reconnaissance and information-gathering phase on the targets, allowing the testing team to understand the exposure surface before moving to action. Then comes searching for and exploiting identified vulnerabilities, always within the limits defined during scoping, documenting each proof of exploitation as the engagement progresses rather than afterward. Finally, results are reported, usually accompanied by a discussion with technical teams to clarify the most critical points. A re-test is often recommended after remediation, to verify that reported vulnerabilities have actually been fixed rather than simply masked.
How often should a pentest be run?
There is no single universal rule, but a widely adopted industry practice is to run a pentest at least once a year on critical systems, complemented after any significant infrastructure change: a new application going into production, a major cloud migration, an authentication system overhaul, or a merger/acquisition that changes the company's technical perimeter. Certain regulated sectors or demanding clients (large accounts, public tenders) may recommend a tighter cadence, sometimes twice a year on the most exposed systems. What matters is aligning frequency with the organization's actual pace of technical change, rather than treating it as a simple annual checkbox disconnected from how the information system evolves: a company shipping new features every month has an exposure surface that changes far faster than one whose infrastructure rarely changes.
What a good pentest report should contain
A quality report goes beyond a simple list of technical vulnerabilities. It should include an executive summary understandable by non-technical leadership, explaining in a few paragraphs the main risks and their potential business impact without unnecessary jargon. It should also include a prioritization of findings based on real impact and ease of exploitation (not just a generic severity score), detailed proof-of-concept evidence for the technical team responsible for fixing issues, precise enough to reproduce the problem, and concrete rather than generic remediation recommendations — stating exactly what to change, not just "strengthen security." A good report allows both decision-making (leadership) and action (technical teams) without needing to be re-translated internally before it can be used, which considerably speeds up the remediation cycle. One last element sets the most useful reports apart: a clear assessment of residual risk after remediation, helping the organization know whether the tested scope can reasonably be considered secure or whether points still need monitoring.