Which approach to choose for conducting a penetration test?

🤔 How to choose the right approach for conducting a penetration test?

Black Box, Gray Box, White Box?

In the constantly evolving world of cybersecurity, where cyberattacks are becoming increasingly sophisticated, conducting penetration tests has become a necessity for businesses concerned about protecting their IT systems and sensitive data.

These tests, often referred to as black box, gray box, and white box tests, are crucial components of any robust IT security strategy. Each type of test offers a unique approach to assessing information system security and identifying potential vulnerabilities that could be exploited by cyber attackers.

Black Box, Gray Box, White Box?
But what is the difference between these three terms? And how do you choose which one is best for you? Trackflaw enlightens you just below 😉

Part 1 - Black Box testing


Definition and Approach

Let’s start with the first approach, often used, but incorrectly 👎

But first, a reminder about penetration testing.

Black box tests are conducted without any prior knowledge of the targeted system. This method simulates an external attack by a cyber attacker who does not possess any internal information about the company’s IT systems. The goal is to evaluate the system’s security based solely on publicly accessible information (URLs and IPs), as a real attacker would.


There are advantages to using this method…

The main advantage of black box testing is its ability to reveal vulnerabilities that could be easily exploited by external attackers. These tests provide a realistic perspective of how an uninformed attacker could breach the systems.


… but it also has disadvantages (and significant ones)! 🙁

However, black box testing can be more limited in terms of depth of analysis. Without access to the source code or internal configuration, some types of internal vulnerabilities could remain undetected.

Moreover, this method may require more time to identify security flaws, as the auditors must first discover and understand the system’s structure. And I confess, it’s often very frustrating! 😭

Perfect for Small Budgets

Black box security audits are suitable for quickly covering wide perimeters and for a small budget. However, be aware of the lack of comprehensiveness in the tests performed.

Trackflaw recommends black box for a quick and regular flash security audit on perimeters with limited risks.

Part 2 - Gray Box testing


Definition and approach

Gray box tests represent an intermediate approach, where the tester has limited or partial access to internal system information. This method combines elements of black box testing. It allows the tester to understand certain aspects of the system while exploring external vulnerabilities. Typically, in addition to URLs and IPs, the auditor receives application accounts and sometimes documentation.


This method is often considered more efficient in terms of time and cost compared to black box testing. By having partial access to internal data, auditors can more precisely target their efforts, leading to quicker identification of potential security flaws.

🤨 But this method still has disadvantages…


Although gray box tests offer a balance between the other two methods, they may not be as comprehensive as white box tests in terms of detecting internal vulnerabilities. Moreover, this method assumes that the tester has a certain level of prior knowledge, which may not fully reflect an external attack.

The Right Balance
Gray box ensures a good balance between comprehensiveness and Trackflaw recommends gray box for a quick and comprehensive security audit of a web application while respecting a limited budget.

Part 3 - White Box testing


Definition and approach

White box tests, often called code-based “penetration” tests. Note that this term is to be avoided. It is advised to favor the term penetration testing in common French language. The elements of white box testing include those from gray box: URLs, IPs, and application accounts, plus the source code.

This test involves complete knowledge of the source code, architecture, and documentation of the system. Auditors use this information to perform an in-depth analysis of the system’s internal security.


The main advantage of white box testing is its ability to identify vulnerabilities deeply embedded in the source code and system configuration. This method allows for a comprehensive evaluation of internal security, including aspects such as code logic, management of sensitive data, and integrated security measures.


However, white box testing can be very complex and time-consuming, requiring in-depth expertise in programming and system architecture.

Trackflaw's Choice

😊 This service is probably the best choice!

Trackflaw consistently recommends white box for a complete and comprehensive security audit.

Summary table

To conclude, here is a summary table of the 3 approaches.

Criteria◼️ Black Box🔳 Gray Box◻️ White Box
System KnowledgeNo prior knowledge of the system.Partial knowledge of the application via accounts.Complete knowledge of the system, source code, and documentation.
Advantages- High realism
- Identifies externally visible vulnerabilities
- Balance between depth and realism
- Efficiency in terms of time and cost
- In-depth analysis
- Identifies a majority of vulnerabilities
Limitations- Less depth
- May miss many vulnerabilities
- Less detailed than white box
- Requires some level of prior knowledge
- Time-consuming
- Financially costly
Time and CostRelatively low: 2 to 4 days.Medium: 4 to 6 daysHigh: minimum 5 days
Recommended Contexts- Testing external resilience
- Realistic attack scenarios
- When partial knowledge is available
- For balanced tests
- In-depth internal audits
- Compliance and development standards verification
Type of Attack SimulatedExternal attacker without specific knowledge.Attacker with limited knowledge of the company.Internal attacker or compliance audit.
Example ScenarioSecurity testing of one or more external perimeters.Security testing of an application with limited user identification information.Complete security audit of an application’s code and security configurations.

If you have any questions about this article, feel free to contact Trackflaw on social networks or by email!

⬇️ Follow us on social networks:

🔴 All our videos on YouTube:
📸 Cyber news on Instagram and TikTok: and
👉 Learn more about Trackflaw:
📨 Evaluate your security now: commande (at)