The increasing digitalisation of products, services and processes has also expanded the attack surface exposed to potential cyber threats. Web applications, APIs, corporate infrastructures and connected devices may contain vulnerabilities that, if not identified in time, could compromise sensitive information, affect system operation or even lead to service disruption.
A penetration test (pentest) is a security assessment in which techniques that could be used by an attacker are simulated in a controlled manner to identify vulnerabilities, determine whether they can be exploited and assess their potential impact on a system.
Unlike an automated vulnerability assessment, penetration testing is not simply a matter of running tools against a system. It is a planned and structured process that requires defining in advance what needs to be assessed, the scope of the testing, the methodology to be followed and how the results will be documented.
So, what should be considered when conducting a penetration test? Let’s take a look at some of the key aspects.
Objectives of a Penetration Test
At its core, penetration testing aims to answer a fundamental question: could an attacker compromise the confidentiality, integrity or availability of the system?
This could involve gaining unauthorised access, modifying data, disrupting a service or causing the system to behave in an unexpected way.
The specific objective will depend on the context and the system being assessed — an API, a web application, a medical application, an internal infrastructure or a connected device, for example — but the underlying principle remains the same: to identify vulnerabilities and determine the extent to which they represent a real risk to the organisation.
Types of Penetration Testing: Black Box, Grey Box and White Box
Before testing begins, the approach must be defined according to the level of information available about the target system.
Black Box
The penetration testing team has no prior knowledge of the system. This approach more closely simulates the perspective of an external attacker.
Grey Box
The team has partial information or access, such as standard user credentials or selected technical documentation.
White Box
The team has extensive knowledge of the system, which may include source code, architecture, technical documentation and credentials.
The choice between Black Box, Grey Box and White Box testing determines the scope and depth of the assessment, as well as the types of attack scenarios that can be evaluated.
Phases of a Penetration Test
Although the process may vary depending on the target system and the objectives defined, a penetration test typically includes the following phases:
- Scope definition: the systems, applications or components to be tested are identified, together with the constraints and conditions of the assessment.
- Information gathering: relevant information about the environment and potential attack vectors is collected.
- Vulnerability identification and analysis: potential weaknesses are identified through a combination of automated techniques and manual analysis.
- Controlled exploitation: where appropriate, identified vulnerabilities are exploited in a controlled manner to determine their exploitability and potential impact.
- Impact assessment: the actual risk associated with each vulnerability and its potential consequences for the system or organisation are evaluated.
- Documentation and reporting: evidence is documented and the findings are presented together with appropriate remediation recommendations.
Penetration Testing Methodologies and Best Practices
To ensure appropriate coverage and maintain traceability throughout the assessment, penetration testing can be based on internationally recognised methodologies and frameworks.
OWASP
OWASP (Open Worldwide Application Security Project) provides resources and reference guides for assessing the security of web applications and APIs, including the OWASP Web Security Testing Guide (WSTG) and OWASP API Security Top 10.
OSSTMM
OSSTMM (Open Source Security Testing Methodology Manual) provides a structured methodology for conducting operational security testing.
PTES
PTES (Penetration Testing Execution Standard) structures the penetration testing process from the initial pre-engagement and information-gathering phases through exploitation, analysis and reporting.
Using recognised methodologies helps ensure that testing is conducted in a systematic, repeatable and traceable manner.
Penetration Testing Tools and Techniques
A penetration test typically combines automated tools with manual testing techniques.
Automated tools can be used for activities such as vulnerability scanning, fuzzing and certain exploitation tasks. However, the expertise of a security professional remains essential.
Manual testing can identify issues such as business logic flaws, privilege escalation paths, vulnerability chains and unexpected system behaviours that automated tools may fail to detect.
For this reason, an effective penetration test should never rely solely on the results produced by an automated vulnerability scanner.
H2 — Penetration Test Documentation and Traceability
Documentation is a fundamental part of the process. Each test performed should be recorded, including:
- Test objective.
- Tools or methods used.
- Steps performed.
- Evidence collected.
- Results and conclusions.
This information is not only used to produce the final report. It also enables the client to understand what was tested, how the testing was performed, which vulnerabilities were identified and what their potential impact is.
