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Black Box Penetration Testing

Definition: Black Box Penetration Testing is a software testing technique where the functionality of an application is tested without any knowledge of the internal workings or structure of the application. The tester interacts with the system's user interface by providing inputs and examining outputs without knowing how and where the inputs are worked upon.

What is black box penetration testing

Black box penetration testing can be used to simulate an external cyber-attack. Testers, who play the role of attackers, try to find security vulnerabilities that could be exploited. This approach is effective in identifying issues related to data input, output processing, and so on, but it may not uncover problems related to internal code structure or logic. Black box testing is ideal for simulating the approach of potential attackers, as it scrutinises the external aspects of the system. Which is by far the most common approach of todays attackers.

Black box testing relies on external expectations of functionality (e.g., software requirements, specifications) to create test cases and is considered beneficial because it evaluates the system from an end-user perspective and does not require the tester to be a developer or have direct access to the source code. But how does it work exactly? What sets it apart from Grey and White Box Testing? Let’s dive into the nitty-gritty of Black Box Penetration Testing, exploring its methodology, real-world examples, and how it compares with other testing paradigms.

The image shows three boxes, a grey box, a white box and a black box.

Black box penetration testing methodology

At the heart of Black Box Penetration Testing lies a number of methodologies that testers will utilise to scrutinise the application. Each methodology contains a sequence of steps which should be used to effectively test the applications defenses against common security vulnerabilities. Each methodology will be broken up into different steps, which typically follow a structure:

  • Intelligence gathering: Testers collect available information to identify potential entry points. Tools and techniques like domain name searches, network enumeration, and mapping tools (Burp Suite, Nmap, Nuclei, OWASP ZAP etc) are used to gather as much information as possible from the systems within the scope.
  • Vulnerability Analysis: Utilising the information gathered, testers hypothesisse where the system’s vulnerabilities might lie and how they can be exploited by attackers.
  • Exploitation: Testers attempt to breach the system using the vulnerabilities identified. Success in this phase often requires creativity, persistence and the testers knowledge and experience of exploiting issues they have seen before.
  • Post-Exploitation: Once exploited, the goal is to understand the level of access gained and to identify further exploitation opportunities.
  • Analysis and Reporting: The findings are compiled into a comprehensive report detailing vulnerabilities, the methods used to exploit them, and recommendations for remediation.

This general methodology, while systematic, requires a high degree of creativity and adaptability from testers, making each test a unique challenge.

Black box testing methodologies (List)

Organisations like OWASP (Open Web Application Security Project) and NIST (National Institute of Standards and Technology) advocate for using a combination of testing methods to achieve a comprehensive security assessment. Below you will find the most popular testing methodologies used by penetration testers today:

Black box penetration testing tools (List)

The world of black box testing tools is ever-growing, with more companies and the open-source community developing more efficient, robust tools to test software.

  • Burp Suite – Offers a comprehensive solution for web application security checks, including both automated scanning and tools for manual testing.
  • Wireshark – An award-winning network protocol analyser that helps capture and interactively browse the traffic running on a computer network. It’s open-source and available for various platforms. Visit Wireshark’s website for more information.
  • Metasploit – The most widely used penetration testing framework in the world, which helps in verifying vulnerabilities, managing security assessments, and improving security awareness.
  • Nuclei – Nuclei is a fast and customisable vulnerability scanner that uses simple YAML-based templates for targeted security assessments across applications, infrastructure, cloud platforms, and networks.

Black box vs grey box penetration testing

When it comes to Black Box and Grey Box Penetration Testing, the main difference lies in the amount of information provided to the testers before they start their assessment of the scoped assets. Grey Box Testing offers them a peek behind the curtain – some knowledge about the internal workings, such as architecture diagrams, documentation and understanding from the client of the environment being tested. This middle-ground approach allows for a more focused test, balancing the external perspective of Black Box Testing with the insider knowledge of White Box Testing. Grey box penetration testing is by far the most popular testing medium.

Black box vs white box penetration testing

Contrasting even more starkly with Black Box Testing is White Box Penetration Testing. White Box Testing involves full transparency, where testers have access to all internal codes, structures, and documentation. This method allows for a thorough examination of internal security mechanisms but lacks the realism of an external attack that Black Box Testing offers. In todays world, white box testing is often deployed via software packages that the client will deploy against the assets in search of security issues and misconfigurations.

Black Box Testing Examples

Let’s go so some examples of Black Box Testing using real-world examples, and probable outcomes:

Website Security Testing for a Retail Company

A retail company’s core public-facing website requires a black box penetration test. The website is built with Django, alongside a Django Rest Framework RESTful API, no user account or API documentation is given. The testers have no access to the source code of the application, the tester is tasked with conducting the assessment using techniques to mimic the actions of an external attacker with no knowledge of the system.

Outcome: The testers discover an SQL Injection vulnerability on the products page. The vulnerability allows the attacker to access the customer database by crafting an SQL query. Using this vulnerability, the tester was able to obtain a large amount of customer data. The company patches the vulnerability via using a combination of input validation practices and alongside prepared statements. (More information on SQL Injection remediation can be found here)

Wireless Network Security Testing for a University

A university wants to ensure that their new campus wireless network is secure from the unauthenticated perspective. They hire a penetration tester to conduct the assessment. The tester is given the SSID of the network as the only information, to ensure that no other sensitive networks are attacked. The tester is tasked with attempting to breach the network and laterally pivot inside the network.

Outcome: The tester exploits the wireless network by capturing the password hash over the air. The tester cracks the hash using Hashcat, the password was 8 characters, consisting of a word, followed by numbers. The tester authenticates with the Wi-Fi and discovers no other protections exist limiting device access, due to a failure of network segregation. The tester can communicate with core Active Directory services and pivot further into the university’s network. The university responds by producing a security password policy for all networked devices, enforcing a 12-character limit, thereby limiting the likelihood of an attacker cracking the password. The university also properly segregates the network to ensure an attacker cannot pivot into other network segments.

Network Penetration Test on Remote Working Infrastructure

A company has recently migrated to a remote working infrastructure, they wish to assess the security of the remote access infrastructure to ensure that it cannot be exploited from an external perspective. The targets include the VPN services, collaboration tools, and data storage software used to allow the employees to work remotely. They hire a penetration testing company, given a limited scope which consists of the IP addresses for the external hosts.

Outcome: The tester discovered an issue with the document-sharing software used by the company. The software allows for guest access to the system, with limited functionality. The tester discovers that the URLs provided when sharing the documents are easily guessable, the attacker uses BurpSuite’s intruder tool to cycle through all of the 6-character identifiers, and the attacker manages to obtain a high volume of the sensitive documents. The attacker also discovers that users with guest access can access the documents without issue, highlighting an issue in the access controls. The company responds by limiting access to the document-sharing platform and ensuring that it is only accessible via the VPN, the company also patches the software, as the vulnerability had already been fixed in later versions.

Key Characteristics:

  • User’s Perspective: Testing is done from the perspective of the end-user, not the developer.
  • No Internal Knowledge Required: The tester does not need to know the programming languages, source code, or architecture.
  • Functional Testing: Focuses on what the system does, rather than how it does it.
  • Dynamic Analysis: Involves executing the software to explore its behaviour under various conditions.


  • Real-World Example: A cybersecurity firm conducts a black box penetration test on a web application to uncover vulnerabilities such as SQL injection and cross-site scripting without any prior knowledge of the app’s internal coding.
  • Hypothetical Scenario: A company releases a new mobile application and hires a test team to perform black box testing. The testers check the app’s responses to unexpected inputs and ensure that features like user authentication and payment processing function correctly.

Related Terms:

  • Penetration Testing: A type of security testing in which a system is analysed for potential vulnerabilities to hacking or unauthorised access, which can employ black box testing methodologies.
  • White Box Penetration Testing: A testing approach that evaluates the internal structures and workings of an application, unlike black box testing.
  • Functional Testing: A type of black box testing that bases its test cases on the specifications of the software component being tested.

Learn better from a video? Check out this YouTube video that best explains Black Box Security Testing

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