Penetration Testing 101: What You Need to Know

May 12, 2021
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4 min read

On the digital battleground, enterprises need a way to make sure their defenses work. Penetration testing (or ‘pen testing’) offers the type of attack you might encounter, but in a controlled case. With pen testing, people intentionally attack an app or network to check on its security posture. This lets enterprises realistically test the effectiveness of their digital security program. A group of technicians use their experience, along with specialized penetration testing tools, to probe defenses in search of vulnerabilities, misconfigurations and other weaknesses. Let’s take a look at how pen testing works, its pros and cons and how it might apply to your organization.

What Is Penetration Testing?

Penetration testing generally comes in one of three different methods. These are as follows:

  • Black box penetration testing: This type of pen testing emulates a real-world digital attack where the intruder doesn’t know the organization’s underlying infrastructure, applications or source code. They’ll use automated processes for an extended period of time to search for vulnerabilities in a trial-and-error approach.
  • White box penetration testing: As opposed to a black box pen test, a white box pen test is where a tester has full knowledge of the underlying architecture and source code. They can use this knowledge to conduct a thorough examination in less time. However, they’ll need specialized tools and potentially more time to figure out what to focus on before getting started.
  • Gray box penetration testing: A blend of black box and white box testing, a gray box pen test uses both manual and automated methods. The testers use what they know to find weaknesses, exploit them and see how far their false attacks can take them.

Using one of these approaches, the testers can then perform one of several pen testing exercises. First, they can conduct network penetration testing, perhaps the most common type. They search for vulnerabilities in the network infrastructure both locally at the client side and remotely from the outside world. Next, they can plan for and invest in a web app pen testing engagement. In this case, they check the endpoints of all web apps. They can test for client-side security holes that emerge locally. This kind of test can also spot areas of human weakness that open businesses up to social engineering attacks.

So how is pen testing different from other types of testing? For example, red teaming mimics a pen test in that false attackers have a set goal for the exercise. But red teaming simulates an advanced threat actor using evasion and stealth to test how an organization’s defenders (known as the “blue team”) respond. In contrast, blue teams know about a pen test beforehand.

Pen testing is also not the same as having a public bug bounty program, which invites hackers and security researchers to report real vulnerabilities in exchange for a bounty.

The Benefits and Challenges of Penetration Testing

The benefits of a pen test are many. It’s one of the primary means by which organizations can build a list of documented vulnerabilities and risks. At that point, you can rank those risks based upon their impact to the business and fix them accordingly. This will help ensure business continuity by preventing an incident from disrupting crucial work. It can also protect clients and partners as well as review (and possibly make changes to) their existing security investments.

That said, pen testing isn’t without its challenges. Pen testers are consultants who might be double-booked across multiple engagements. As a result, they might be limited in the time they have to try to penetrate a client’s network, and in that time, they might try to reuse tactics that worked against other clients. This type of approach might not represent the real security threats confronting different groups potentially spread across different industries — more so when just a couple of people from the same company are conducting pen tests just a few times a year.

Last but not least, pen tests might point out vulnerabilities, but these engagements are not folded into organizations’ security programs. So these entities might lack the resources and workflows to address them in a timely manner.

How to Maximize the Impact of a Penetration Test

Keeping in mind those challenges, organizations need to invest in maximizing the impact of their pen tests. First, focus on how to best prepare for one. This should involve planning well in advance for the test by providing a sufficient plan that documents the in-scope systems to the testers.

Next, contribute to a smooth test by not fixing things unilaterally while the engagement is in process. That’s not to say you can’t implement security fixes during the test. But you should be in contact with the testers about their decision. This prevents you from holding up an engagement and forcing the testers to keep circling back to the same systems as changes are made.

Organizations also need to act upon the results of their pen testing once it’s done. Part of this involves fixing specific issues found by the testers. But it also involves reviewing and augmenting vulnerability management programs, threat intelligence feeds and other security best practices.

Combine Pen Testing With Other Tactics

Last but not least, organizations need to remember that they are not bound to one form of security testing. They can engage in different pen testing tactics and different types of pen tests. They can also establish an ongoing bug bounty program as well as explore other security testing paradigms, such as redteaming. Together, these tests can provide their own unique glimpse into an organization’s security strengths and weaknesses. The organization can then use that knowledge to harden its digital security posture going forward. They’ll have the assurance they’ve already faced some of what an attack could bring.

David Bisson
Contributing Editor

David Bisson is an infosec news junkie and security journalist. He works as Contributing Editor for Graham Cluley Security News and Associate Editor for Trip...
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