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Why Grey-Box Pentesting is the Best Strategy


Penetration testing is a type of intrusion test where a company audits itself (or outsources the effort to experts like Packetlabs) to discover vulnerabilities in their networks and systems. Ethical hackers, who are also known as white-hat hackers, carry out penetration testing. They set out to deliberately target the organization's systems in order to gain a better understanding of the security gaps and help guide the organization’s cyber defence strategies. It is recommended to complete a pentest at least once a year to stay ahead of evolving threats.

Within the realm of penetration testing, there are several options: white-box, grey-box and black-box. While each type of test has its pros and cons, the right approach for your organization can depend on your goals, budget, timeline and scope.

Here is a summary of Black-Box vs Grey-Box vs White-Box


What is a grey-box pentest?

A grey box penetration is a mix of white box and black box pentesting, just like the colour grey is a combination of black and white. 

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 simulates an attacker that has already penetrated the perimeter and has limited internal access to the network.

A grey box pentest is most beneficial to:

  • Simulate an insider threat

  • Test an application to check authenticated user access

In an insider attack, a user could damage the target system. Grey-box pentesting can simulate this threat to understand the level of access a privileged user could gain to cause damage. It can also verify user authentications and check if a particular user can access another user’s data.

With a grey-box pentest, testing speed is slightly quicker than a black-box pentest since the tester starts with more information. Since testers are not entirely in the dark, they can simulate attacks more efficiently and go beyond what would be possible in black-box mode. A grey-box pentest achieves a good balance between the efficiency of the black-box method and the depth of the white-box approach.

In recent years, almost all high-profile cyberattacks have involved intelligent, persistent adversaries who took the time to conduct some reconnaissance on their target organization’s environment. This gives them practically insider-level knowledge and allows them to launch attacks larger in scope and scale than they would be otherwise.

A grey-box pentest strategy is often the best strategy in such scenarios since it delivers depth, efficiency, coverage, and authenticity.


While all three types of penetration testing have their benefits and drawbacks, selecting the right penetration testing strategy for your business depends on the systems you want to test, your cybersecurity goals, and how much information you can/want to provide to the tester. Grey-box testing is generally the best strategy for most businesses as it is the most efficient, quicker to complete and budget-friendly.

The Packetlabs penetration testing team is comprised of qualified and certified Ethical Hackers who know what it takes to strengthen – and weaken – your organization’s systems. The team creates easy-to-read reports that can be shared with company executives or board members.

Contact the Packetlabs team today!