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Black-Box vs Grey-Box vs White-Box Penetration Testing


You're looking at getting a penetration test done, and you want to know what kind of test is right for you. You've heard of black-box, grey-box, and white-box testing, but you're not sure what the differences are or which test will give you the best level of protection again malicious cyberattacks.

When it comes to selecting the type of testing, several of the most commonly asked questions that arise include:

  • Why is it recommended to provide and use credentials from the client when testing an application?

  • Does the penetration testing organization need to be whitelisted during the engagement?

  • Shouldn’t the testing engagement focus on replicating an external hacker trying to penetrate all defenses to evaluate our implemented security accurately?

  • Isn’t it cheating to get insider knowledge about the network or application before the test?

To help answer those questions, it is best to look at the pros and cons of each of the three penetration testing types: black-box, grey-box, and white-box.

Black-Box Penetration Testing

In a black-box engagement, the tester is not granted any access to the applications or networks. The tester must perform reconnaissance to obtain the sensitive knowledge needed to proceed. 

This type of testing is the most realistic simulation of a cyberattack. However, it also requires a great deal of time and has the greatest potential to overlook a vulnerability that exists within the internal part of a network or application. A real-life attacker generally does not have any time constraints and can take months to develop an attack plan waiting for the right opportunity.

In addition, many defensive tools exist within networks to help prevent an existing vulnerability from being exploited.  Some web browsers now have settings to circumvent an attack even if a weakness still exists. All that may be required to exploit that vulnerability is a variation of settings or a connection from a different browser version. 

Just because a configuration prevents the vulnerability from being found or exploited does not necessarily mean the vulnerability does not exist or is actually being mitigated. It only means that some outside force is buffering the result. This can result in a false sense of security that may be exploited at a later time by someone who has more time to explore this attack surface more greatly.

Grey-Box Penetration Testing

With grey-box testing, the tester is granted some internal access and knowledge that may come in the form of lower-level credentials, application logic flow charts, or network infrastructure maps. This can simulate an attacker that has already penetrated the perimeter and has limited internal access to the network.

Starting with some background information and low-level credentials helps to a more efficient and streamlined approach. This saves time on the reconnaissance phase, allowing the consultants to focus their efforts on exploiting potential vulnerabilities in higher-risk systems rather than attempting to discover where these systems may be found.

In addition, some types of vulnerabilities can only be discovered by looking at the source code or configuration settings. A tester with no prior knowledge would likely never stumble across these less common issues.

White-Box Penetration Testing

White-box testing allows the tester to have complete open access to all applications and systems. The tester is granted high-level privileges access to the network and can view source code.

White-box testing aims to identify potential weaknesses in various areas such as logical vulnerabilities, potential security exposures, security misconfigurations, poorly written development code, and lack-of-defensive measures. This type of assessment is more comprehensive, as both internal and external vulnerabilities are evaluated from a 'behind the scenes' point of view that is unavailable to typical attackers.

Once again, because so much time is required to review all aspects of the system thoroughly, white-box testing is generally reserved for high-risk systems or those that process sensitive data.

A Summary of Black-Box vs Grey-Box vs White-Box


Which Approach is Right for Your Organization?

A penetration test aims to identify potential vulnerabilities in your systems before an attacker does. The level of access and knowledge granted to the tester will determine how comprehensive and accurate the test results will be.

Defining the concerns you would like to resolve is essential to designing a customized approach that will effectively meet the necessary security requirements and result in the most value from your penetration testing investment.

Packetlabs' team of highly skilled and OSCP-certified ethical hackers customize every engagement to ensure the most thorough penetration test possible. We understand that not every architecture or application fits into a predefined box and will require an adaptive testing methodology to develop a solution that works best for your organization.

Automated testing accounts for only 5% of what we do. The other 95% consists of manually simulated real-life attacks, so whether you are looking for a black-box, grey-box, or white-box assessment, Packetlabs has the experience and expertise to help you secure your system and prevent costly data breaches.

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Our ethical hackers provide expert-level penetration testing services to help protect and secure your organization from costly cybersecurity breaches. Get a free, no-obligation quote today!