What are Black Box, Gray Box, and White Box Penetration Testing?

Running a business isn’t easy, and potential data breaches make it even more challenging. Information related to your client, coding, revenue, and employees is crucial. That’s why regular penetration testing is so important. The goal is to uncover vulnerabilities by performing an actual cyberattack on your system.

According to the style and approach, the three types of penetration testing are black box testing, gray box testing, and white box testing. Let’s discuss and compare them in detail. 


Black Box Testing

A black box penetration test, also known as an external penetration test, is performed when a white-hat hacker has no prior information about the security policies, architecture diagram, source codes, etc. of your IT structure. Conducting a penetration test step by step this way mimics the actions of a real-life cyberattacker. .

In black box penetration test methodology, the company allows white-hat testers to impersonate an unprivileged black-hat attacker. It’s like an actual cyberattack, so it gives you the best idea about your system’s vulnerabilities. 

The white-hat tester creates a map of attack and all the entry points (just like a black-hat hacker) for observation and analysis required to hit your system. 

The benefit of the black box penetration testing methodology is its ability to detect complex vulnerabilities like cross-site scripting (also known as XSS, which enables threat actors to disrupt the operation of web pages), SQL injections, server misconfiguration, etc. XSS.  

Now that you’re fairly aware of what a black box penetration test is, let’s move to the next testing approach.


Gray Box Testing

So, what is a gray box penetration test? Unlike black box penetration testing, the tester has basic knowledge about your system, applications, and network. With gray box penetration testing, the tester gets low-level credentials, network maps, and logical flow charts. 

This saves time consumed in various stages of penetration tests. Gray box penetration testing is helpful as some vulnerabilities can only be found by looking at source codes. Such susceptibilities are left unidentified in a black box penetration test.


White Box Testing

The easy white box penetration testing definition is as follows: It’s a style of testing in which the tester is privileged to get all your system’s information. This means they already have credentials, source codes, infrastructure maps, and all that’s required to attack your system. 

The white box penetration testing technique is basically applied to spot potential weaknesses. This can be a poorly written code, or absence of robust security measures.

Testers prefer using the white box approach for high-risk systems only as it takes time. Nonetheless, it still efficiently fulfils the goals of a penetration test.


Black Box vs. White Box vs. Gray Box Penetration Testing

Let’s compare black box vs. gray box vs. white box penetration testing. This will help you decide the most appropriate technique as per your expectations, budget, and requirements. Knowing the differences also gives you insights on using the right penetration testing tools in future.


  • The black box penetration test is the least expensive. However, its benefits are limited. It identifies fewer vulnerabilities and is therefore not very promising. 
  • The gray box penetration testing method is less expensive and detects many vulnerabilities.
  • The white box penetration test is the most expensive, and its returns are very constructive. This has the highest dollar-per-vulnerability ratio. However, it takes more time, so it’s reserved for sensitive or high-priority cases only.


  • With black box penetration testing, the  simulated attack is conducted in the same situation as that of a threat actor. It’s an ideal form of penetration testing to identify and patch weaknesses.
  • Now, among black box vs. gray box vs. white box penetration tests, gray box takes the middle rank. Only a limited amount of information is given to hackers, so it’s moderately accurate.
  • The white box penetration technique is the least accurate because it allows testers to hack a system in a situation that’s far from reality. So, unlike the tester, a threat actor is never aware of all the details.

Efficiency and Speed

  • As aforementioned, black box is the fastest method. However, it’s not as efficient as other methods since testers are nonprivileged. As such, they can miss vulnerabilities which black-hat hackers can use as entry points.. 
  • Between black box vs. gray box penetration testing, the latter might lose some points on speed, but the efficiency is higher. A penetration testing expert is moderately privileged, which helps them steer their focus on hacking the system for specific vulnerabilities.
  • With black box vs. gray box vs. white box penetration testing, white box wins all the brownie points for its efficiency, but it’s the slowest method as well. 


  • The coverage in black box penetration testing is the least as it doesn’t cover inside details such as code, server logic, and development methods.
  • In gray box testing, everything is tested except source code or binaries. This is because only limited information is provided.
  • The white box penetration testing technique involves assessment of every single branch.


While all the testing strategies are somewhat hazardous, white box penetration testing puts your system at the most risk. Hired hackers have so much more access to the smallest cracks of your system—which they can exploit if they’re not trustworthy.


Which is Right for Your Organization?

Black box methodology reveals limited vulnerabilities and mainly focuses on the login page only. It’s the cheapest among the three, but still, it could be expensive for small projects. SaaS companies prefer gray box penetration testing due to its fair efficiency and accuracy. White box penetration testing is only deployed for critical and alarming situations because it’s very expensive and time-consuming. 

So, if you’re considering black box vs. gray box vs. white box penetration testing, go for the gray box if you can stretch your budget a little. Gray box is typically the most prudent choice for businesses of all sizes. It also balances the risks and benefits of penetration testing.

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*** This is a Security Bloggers Network syndicated blog from EasyDMARC authored by Knarik Petrosyan. Read the original post at: