Black Box Penetration Testing: A Guide To Code Quality

Black box penetration testing is a testing technique that focuses on the functionality and behavior of software without taking into account its internal structure or source code. This testing approach treats the software as a black box, wherein the tester only evaluates its inputs and outputs to ensure that it meets the requirements and specifications.

Software development is a complex process that involves several stages, including design, coding, testing, and deployment. Testing is a critical part of software development that aims to identify and eliminate bugs and defects before the software is released. One of the most popular testing techniques used in software development is black box testing.

From an external black box penetration testing standpoint, we’re testing everything you’ve opened to the internet that your staff or clients can use.

Read more: What is White Box Penetration Testing?

Read more: What is Grey Box Penetration Testing?

Black Box Penetration Testing: Techniques and Importance

Black box penetration testing is an essential process that you can use to evaluate the security level of your network, application, or system. It involves testing the system from the perspective of an attacker so that you can identify and mitigate security risks before they are exploited by cybercriminals.

In this section, we will give you an overview of black box penetration testing, its importance, and the different types of techniques used to achieve it.

Types of Black Box Testing Techniques

Network Testing

Network testing is a technique used to evaluate the security of your network infrastructure. It involves the use of automated tools to scan for open ports, vulnerabilities, and other weaknesses that could be exploited by attackers. Two of the most important types of network testing techniques are:

  1. Port Scanning – This technique involves checking all the open ports on your network to identify any vulnerabilities. This process involves evaluating whether there are any open ports that should be closed or monitored.
  2. Vulnerability Scanning – This technique involves scanning your network for known vulnerabilities that could be exploited by cybercriminals to gain access to your system. The scan will identify vulnerabilities in your network infrastructure, such as outdated software, weak passwords, or misconfigured settings.

Web Application Testing

Web application testing is a technique that is used to evaluate the security of your web applications. It involves identifying vulnerabilities that can be exploited by attackers. Two of the most common web application testing techniques are:

  1. SQL Injection – This technique involves injecting malicious code into a web application’s database to retrieve confidential data.
  2. Cross-Site Scripting – This technique involves injecting malicious code into a web page to trick the user into providing sensitive data such as login credentials.

Wireless Network Testing

Wireless Network Testing is a technique used to evaluate the security of your wireless networks. It involves identifying vulnerabilities that could be exploited by cyber criminals to gain unauthorized access to your network. Two critical types of wireless network testing techniques are:

  1. WEP Cracking – This technique involves cracking the Wired Equivalent Privacy (WEP) encryption protocol used in wireless networks to protect data from being intercepted. It is important to know whether your network is using WEP encryption, as it is an outdated protocol and is easily cracked.
  2. SSID Spoofing – This technique involves creating a fake wireless access point to trick users into connecting to it, so that cybercriminals can intercept their traffic.

Phases of Black Box Testing

Black box testing is performed as software testing technique used to assess the quality of software from an end-user’s perspective. This technique helps to detect errors, bugs, and other issues in the software application. In black box testing, the tester does not have knowledge of the internal workings of the software application being tested. Instead, the tester focuses on the inputs and outputs of the software application.

There are four main phases of black box testing:

  1. Planning Phase
  2. Preparation Phase
  3. Execution Phase
  4. Completion Phase

Planning Phase

During this phase, the test plan is created, and the test designer establishes the test case. The test plan outlines the goals, objectives, and scope of the testing. The test case design involves defining the inputs, actions, and outputs to be tested.

Preparation Phase

In this phase, the test environment is set up, and the test data is prepared. The test environment includes the hardware and software used to carry out the testing. The test data is prepared to ensure that the testing covers all possible scenarios.

Execution Phase

This phase involves the actual execution of the test cases. The tester performs black box testing case execution based on the inputs, actions, and expected outputs. The tester also reports and tracks any defects found during the testing process.

Completion Phase

The completion phase involves the test closure activities and the test summary reports. The test closure activities include post-test reviews, documentation, and sign-off. The test summary reports provide a detailed overview of the testing process, including the test environment, test data, test results, and any defects found.

Importance of Phases in Black Box Testing

Each phase of black box testing is essential to ensure that the testing process is thorough and effective.

Ensures Test Coverage

The planning and preparation phases allow testers to identify the test cases needed to cover all possible scenarios. This helps to ensure that the testing process is comprehensive and covers all possible areas of the software application.

Improves Quality of Software

The execution and completion phases help to identify and eliminate defects in the software application. This ensures that the software application is of high quality and meets the requirements of the end-users.

Increases Productivity

The planning and preparation phases help to streamline the testing process, reducing the time needed for testing. This increases productivity and allows the software development team to focus on other crucial aspects of the software development process.

Challenges in Phases of Black Box Testing 

Black box testing also faces several challenges during the different phases of the testing process.

  • Time Constraints
  • Resource Allocation
  • Integration Issues

Time Constraints

The testing process may face time constraints due to project timelines, which can limit the available time for thorough testing.

Resource Allocation

Testers may encounter challenges in allocating sufficient resources for the testing process, including staffing, hardware, and software.

Integration Issues

Integration issues with other software applications can affect the accuracy of the testing process and may lead to errors and defects in the software application.

The different phases of black box testing are critical to achieving thorough testing and ensuring software quality. Although black box testing can face challenges, it is essential to address these challenges to ensure that testers can execute effective black box testing.

Examples of Black Box Testing

Black box testing can be applied in different stages of software development life cycle, including GUI testing, functionality testing, integration testing, regression testing, and acceptance testing.

  • GUI Testing focuses on the graphical user interface of the software to ensure that it is easy to use, intuitive, and error-free.
  • Functionality Testing involves evaluating the software’s features and functions to ensure that they operate as intended and perform the required tasks.
  • Integration Testing involves testing the software’s interactions with other software components to ensure that it works seamlessly with other systems.
  • Regression Testing involves retesting the software after changes have been made to ensure that the alterations or modifications have not introduced new defects.
  • Acceptance Testing involves testing the software in a real-world environment to ensure that it meets the user requirements and specifications.

Recommended Five Phases of Black box Testing by Dixons Carphone’s CISO

Dixons Carphone’s CISO, Paul Midian, recommends five stages of black box penetration testing.


Ethical hackers investigate the consumer prior to the tests to get a good view of the objective. The customer’s website, WHOIS directories (online archives with domain names), internet search engines, trade journals, and even the yellow pages are also useful outlets to gain a level of knowledge public knowledge.


At this point, ethical hackers can obtain a large amount of information about listening services and ports in order to evaluate the customer’s operating system. TCP-UDP ports 137, 138, 139, and 445, for example, indicate Microsoft OS; SSH on port 22, FT on port 21, and DNS on port 53, on the other hand, indicate Linux OS.

NMap, a tool that uses TCP/IP stack fingerprinting to decide the type of OS, is another choice. The hacker team will also check the network for unreliable dial-in modems (which can be used to get through perimeter defences) and run a vulnerability detector (an automated tool that inspects the network for security breaches and generates a detailed report on the search results).


The enumeration process aims to bind target hosts in order to reveal network attack vectors. Ethical hackers concentrate their efforts on open network networks and shares that could have a direct connection to the customer’s sensitive infrastructure, usernames and user classes (to identify default user or administrator accounts), and banner screens (if misconfigured, they may expose the software and device type).

Gaining access

The climax of the penetration testing operation is gaining entry. The research team then tries to hack the target device by using password splitting, buffer overflows, or DoS attacks on individual network nodes.

Privilege escalation and access maintaining

If the hacker team has gained access to the network without having any preferential privileges, they intend to use password cracking software to achieve administrator level of access and preserve network access. This is achieved by creating backdoors, which are then destroyed by ethical hackers before the experiment is completed.

Advantages of Black Box Testing

Black box testing offers several benefits to software developers and testers. Some of these benefits include:

Helps uncover defects that may have been missed during development: Black box testing can reveal defects that may have been overlooked in the development process, including functionality defects, usability defects, and compatibility defects, among others.

Provides a comprehensive assessment of software functionality: Black box testing evaluates software from the user’s perspective, ensuring that it meets the user requirements and specifications.

Ensuring software meets user requirements: Black box testing helps to identify whether the software meets the user requirements and whether the software can be used effectively.

Reduces the risk of software failure: By testing the software thoroughly, black box testing helps to identify defects and bugs that can lead to software failure or system crashes.

Ensure the usability of the software: Black box testing evaluates the software’s usability to ensure that it is user-friendly and easy to use.

Disadvantages of Black Box Testing

Although black box testing offers significant benefits, it also has its disadvantages. Some of these disadvantages include:

Limited scope of testing: Black box testing only evaluates the software’s functionality and behavior, without considering its internal workings or source code.

Limited knowledge of the internal workings of the software being tested: Testers may not have a complete understanding of the software’s internal and external workings, which can make it difficult to identify certain types of defects.

Time-consuming and expensive: Black box testing can be time-consuming and expensive, particularly when testing complex software systems.

Difficult to test complex software systems: Black box testing may not be suitable for testing complex software systems that are difficult to understand or require specialized knowledge.

May not be reliable in discovering certain types of defects: Black box testing may not always be reliable in uncovering certain types of defects, such as performance defects, security defects, or memory leaks.


Black box testing is a valuable testing technique that can help software developers and testers uncover hidden defects and ensure that software meets user requirements and specifications. Despite its limitations, black box testing remains an important part of the software development life cycle process and should be used in conjunction with other testing techniques to ensure that software is of the highest quality.

This is an essential process that can help you identify vulnerabilities in your network, application, or system so that you can mitigate them before they are exploited by cybercriminals. By using different types of penetration testing techniques, you can ensure that your cybersecurity posture is robust and effective. It is essential to conduct regular penetration testing to stay ahead of emerging security threats and to protect your business and your customers from cyberattacks.

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