Black Box Penetration Testing: What You Should Know

Penetration testing is a reliable way to assess your network, cloud, or physical data security and determine how vulnerable your systems are to would-be attackers.

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Black box penetration testing is just one style of security assessment. Specifically, a black box test mimics a real-life hacking attempt, but the attack tester has no prior knowledge of the target involved.

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The anonymity of black box pen testing can be useful when evaluating vulnerabilities and security hardening needs. However, there are some circumstances where other options might be more appropriate. In this guide, we’ll explore what black box penetration testing involves, and why it’s so popular.

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What Is a Black Box Penetration Test?

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A black box penetration test is a “rehearsal” of a hacking attempt or attack on a system or network. The hacker, or tester, is employed through a cybersecurity firm to launch an external attack without knowledge of any system or data specifics.

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All the attacker has is a simple URL, such as a website or web application, from which an external hacker might usually try to gain access.

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A black box test shows firms how susceptible their systems and data are to random cyberattacks. In many ways, it’s considered the closest you can get to mimicking real-world attacks on operating systems, firewall setups, and more.

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Black box pen tests typically:

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• Hire unbiased testers with limited information on, or no prior knowledge of the client
• Assess whether or not software meets security needs
• Avoid diving deep into intricate source code
• Stick to user interfaces and APIs, therefore mimicking a generic, random attack

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Further down, we’ll explore the pros and cons of black box pen testing in more detail. However, you might want to run a black box test if, for example, you need to test certain sections or parts of a network.

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In many ways, this type of penetration testing is a useful launchpad for discovering hidden weaknesses and potential security flaws. Some companies might use black box testing methodologies to lay the groundwork for wider action, such as upgrading certain software or hardening protocols.

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At Viking Cloud, we generally use a pen testing model that gives our testers a little more information about who they’re attacking. This allows us to go more in-depth with our analysis and recommendations.

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However, we know that black box attacks are some of the most effective penetration testing strategies for certain companies. So, let’s explore how this type of security assessment works in practice, and consider if it’s the right choice for you.

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Steps in a Black Box Pen Test

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Crucially, no two black box assessments are ever the same. Depending on what a client needs, cybersecurity experts might recommend different penetration testing tools or testing methods (such as brute force attacks or SQL injection).

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What all black box missions share, however, is the idea that there’s no insider knowledge. The following steps all take place blindly from an external perspective! The goal is to launch exploratory testing to uncover hidden security issues in need of remediation.

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Reconnaissance

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At the recon stage, testers bring together as much information as possible about their attack target.

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Before mounting an attack, testers might research public details about a company’s web presence, information available through social media, and any publicly accessible IP addresses. This is known as passive reconnaissance because the tester avoids interacting with the target system.

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Testers run active reconnaissance by directly scanning for system vulnerabilities and trying to access open ports before launching an attack. This could, for example, include brute force techniques to bypass password access.

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Active recon tends to be more comprehensive than its passive counterpart. That’s because testers gain more knowledge about a company’s security posture through specific, objective answers. That said, active recon can raise literal alarms!

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Vulnerability Scanning

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Beyond active reconnaissance, black box pen testers dig a little deeper into a system’s security posture by scanning for common vulnerabilities and “easy targets.”

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That might include using Nmap to learn more about operating systems, versions currently running, and any crucial details about IP addresses, user accounts, and roles. All these details can help testers use tools and techniques to break in – without prior knowledge of security setup or misconfigurations.

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Vulnerability scanning is one of the most important steps we recommend clients take alongside hiring penetration testing services. It’s wise to get a 360-degree overview of potential vulnerabilities inside and out.

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After scanning, testers will research the best attack vectors to use that can exploit any specific vulnerabilities found. For example, outdated software versions could encourage attackers to look for publicly known backdoors. Sometimes, experienced ethical hackers will already have toolkits!

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Exploitation

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Exploitation is all about putting the knowledge gained during recon and scanning into practice.

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Here, the penetration tester uses different attack methods to exploit security vulnerabilities and cycles through tools to build recommendations for clients later down the line.

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For example, if a brute force attack doesn’t work, testers might use a completely different approach – such as social engineering to convince employees to let them in!

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Privilege Escalation

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If the tester gains access to a system, only one part of the mission is complete. Upon gaining access, the hacker now needs to see if they can gain access to higher privileges from the inside.

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So, if a tester manages to break into a network at a basic user level, they might escalate their attacks one level of access at a time, gradually working their way up to admin or owner.

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This tells the attacker that the system itself isn’t just vulnerable, but that they can also scale security heights from the inside, too.

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Reporting and Documentation

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At the end of the black box pen test, testers and cybersecurity professionals build a clear profile of their client’s known vulnerabilities, often with extensive documentation.

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This is discussed in detail with the client so that experts can make straightforward recommendations. For instance, they might encourage better password security, additional authentication, extra training on security protocols for staff, and regular software updates.

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Common Black Box Penetration Testing Techniques

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As mentioned, black box pen tests can take different shapes, which means some techniques are more convenient or effective than others. Here are just five types of penetration testing techniques used in black box scenarios.

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Fuzzing

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Testers use fuzz tests to assess how a system reacts to invalid data inputs. So, if they add unexpected data to a form or field, this is called a noise injection. If an application can’t handle a lack of data or unknown characters, hackers can then exploit any errors or crashes that arise.

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Password Attacks

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Password attacking involves guessing security phrases through automated tools and techniques. With brute force and dictionary attacks, for instance, testers can launch thousands of automated password guesses and eventually break into vulnerable systems.

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Password cracking varies in complexity and intensity. Many cybercriminals choose password testing first in the hope that users ignore strength and entropy recommendations.

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To offer some perspective, Microsoft reports that it tracks and repels around 1,000 password breach attempts per second.

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Equivalence Partitioning

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Testers and hackers use this technique to divide data they observe through a target into equivalent classes.

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It’s a type of data organization that enables testers to efficiently assess and scan different classes one case at a time. It’s a resource management technique that ensures tests are conducted swiftly and accurately.

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Decision Table Testing

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Black box testers use decision table testing to organize system inputs and outputs into accessible, easy-to-read tables. This way, hackers have complete oversight of input and output combinations, and can therefore ensure security testing is highly accurate while remaining efficient.

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State Transition Testing

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Black box testers use this technique to assess how software and applications change from one input to another, measured in a sequence.

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Given they have zero prior knowledge of client software before testing, this technique helps black box hackers understand how certain programs react to specific commands – therefore helping to uncover weaknesses.

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Benefits and Drawbacks of Black Box Penetration Testing

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Black box penetration testing is great for uncovering a variety of hidden weaknesses. However, there are some drawbacks that might apply depending on your circumstances. Here are some pros and cons of using this type of pen testing.

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Benefits of Black Box Pen Test

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• You get a clear insight into what a random external attacker can see and do
• It’s highly realistic
• Testing is unbiased and objective
• You can assess the effectiveness of current security controls against external threats
• It’s highly scalable for one-off needs and larger projects

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Drawbacks of Black Box Pen Test

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• It’s not often as comprehensive as white box penetration testing, or gray box tests, which review deeper code and processes
• You don’t always get the full picture and might receive false positives or negatives
• It’s not always easy to localize root causes or destinations
• It’s not ideal for internal threat testing or some application security
• Recon can be time-consuming

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Best Practices for Effective Black Box Testing

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To close, let’s consider a few of the best ways you can make the most of a black box pen test.

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Understand the Requirements

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Before testing, attackers must always understand the basics of how a system works and the security standards expected of it. Black box testers don’t have deep knowledge of client setups, however, they must understand the system’s current position, and what the tests aim to discover.

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Rank Test Cases by Importance

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By ranking test cases, testers can prioritize functions that are critical to the client and therefore focus on them ahead of any others. This helps to ensure resources are used wisely and efficiently and that the most important aspects of an assessment are covered.

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Use Varied Input Data

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Testers must use a range of different inputs to discover how systems and networks respond. By varying data, testers can uncover a broad spectrum of responses and reactions, and therefore get a clearer picture of potential weaknesses.

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Work Closely with Development Teams

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You can’t expect a black box tester to carry out these intensive assessments on their own! By working closely with developers, testers can speed up testing feedback and document recommendations. They can also understand system requirements more closely and share useful insights.

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Black box penetration testing is just one side of a more complex, but highly useful, security analysis plan.

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At VikingCloud, we take a comprehensive approach through white, gray, and black box penetration testing services – in many cases, our testers have full knowledge of clients’ systems.

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If you’d like to learn more, reach out to our team of security experts and let’s discuss your needs.