Blog
Penetration testing

What is Network Penetration Testing? When & How to Start Tests

James Harrison
Author
James Harrison
Senior Content Writer

Key Points

Secure networks are crucial to cybersecurity. Without testing your networks from the outside, you never truly know how secure they are. And if you’re a CTO or security manager, chances are you have to prove your security posture to clients or stakeholders to seal a deal – but where do you start?

Network penetration testing is an essential security measure for any organization, and will go a long way to proving the level of your current security status and processes. So if you’ve got a security questionnaire from a client, don’t just Google the answers. We’re here to help. This guide will take you through the basics of penetration testing, which type is best for your business, how to choose the right provider, and more.

What is network penetration testing?

Network penetration testing, also known as pen testing, is the process of conducting simulated attacks on a network to discover any potential weaknesses which can be exploited by hackers to breach your systems.

Think of it as mapping and investigating your network to find any vulnerabilities so that you can patch and beef up security before any malicious hackers crash the party.

Any attack can be serious, but if you're worried about letting pen testers loose on your network, don't worry – you are in control in terms of the scoping process and setting out the rules of engagement. Scanning tools and ethical hackers conduct network penetration assessments to find potential problems and help you determine solutions to strengthen your defenses, not try to steal your data.  

With penetration testing, you’ll strengthen your cybersecurity posture, bringing threats into focus. Even if you’ve never been breached before, pen testing is crucial for understanding how to improve and stay safe.

Network pen testing is a broad term, encompassing everything from assessing internal systems or private networks that aren’t connected to the internet, to probing external services exposed online. This can include web application penetration testing and APIs as well as examining specialized protocols such as SIP, the protocol which is used to control voice/video calls over a network. Learn more about the different types of penetration testing.

The two types referred to most often - internal and external infrastructure assessments - will be our focus in this post.  

Internal infrastructure pen test

Internal infrastructure penetration testing simulates every organization’s worst nightmare: what happens when a bad actor gains access to your networks from the inside?

Keeping your data safe from insider threats is more important than ever. 60% of all breaches come from people on the inside – whether it’s malicious actors with unauthorized access attacks and social engineering or employees gone rogue – so you must ensure the security of your infrastructure is as strong as possible.  

To do this, a team of penetration testers will try to wrangle their way in where they don't belong - into any sensitive or privileged areas you want bad actors to stay out of.

They'll look for any cracks in your security by finding ways around access controls, aiming to get their hands on stuff they shouldn't. They’ll then provide you with a detailed report so you can promptly start the work of eliminating any flaws that could put sensitive data at risk.  

External infrastructure pen test

External infrastructure network pen testing is different but equally important. It answers the question: how could someone with no prior access gain entry and do harm?  

Unlike an internal network pen test, the external kind usually focuses on your perimeter systems. Anything an outsider could access from the public internet, partner systems, or other outside networks depending on the scope of the test.  

One thing to remember about conducting an external pen test is that it goes beyond just uncovering potential vulnerabilities. It also helps you to understand how those weaknesses can be manipulated and the true risks they pose if a malicious actor were able to exploit them. Knowing that someone can gain access is just the beginning. If you don't know how far they could get, then you don't have the full information available to properly assess the risk.

External network penetration testing services typically employ a combination of techniques to understand your security posture.

Depending on your situational needs, your next assessment may involve credential guessing to find out whether any active accounts have passwords that are easily guessable and external vulnerability scanning to uncover cybersecurity weaknesses.

Why is network penetration testing important?

Hackers are always finding new ways to hack into business systems. But by leveraging the expertise of a penetration testing team or an automated pen testing tool, you can identify and tackle vulnerabilities more effectively – giving your security a boost.

And, with data breaches costing $4.35 million on average in 2022, waiting until you get attacked to fix things is clearly a bad move.  

How to carry out a network pen test

Whether they’re internal or external, most penetration tests take one of two forms: manual or automated.

Manual network penetration testing

Manual pen tests are authorized cyberattacks performed by expert security analysts. In other words, it involves real humans trying to hack your systems using a range of tools and techniques. Along the way, they keep detailed logs, notes, and documentation which they then use to explain the security flaws they found and offer recommendations on how to fix the weaknesses.

Humans have the advantage of understanding IT complexities that automated tools and machines can't. Humans can think like a hacker – critically assessing potential threats and finding creative solutions for maximum protection against malicious activity. Better still, they're trained to spot patterns and weaknesses that could be missed by automated software, as well as accurately identifying false positives, allowing businesses to resolve security issues quickly and more efficiently.

Of course, there is a downside to manual penetration testing. As it occurs at a set point in time — whenever you decide to conduct a test – the pen tester’s report can go out of date almost immediately because your business and its security posture are constantly changing.

A new vulnerability could appear the day after your pen test was conducted leaving you exposed. And, because manual pen testing can be expensive, it’s not cost effective to be done frequently, making it inappropriate for enhancing your security between tests. For that, you’ll need…  

Continuous network penetration testing

Bridging the gap between a point-in-time test and vulnerability scanning, Intruder offers a unique continuous penetration testing service, where our pentesting team look for critical vulnerabilities in your systems on an ongoing basis. Learn more about it here.

How to choose a network pen testing vendor

If you’ve been shopping around, you’ve probably noticed there’s a sea of formal qualifications to choose from. From CREST Certified Tester in Infrastructure (CCT INF) to Offensive Security’s OSCP, it can all seem pretty confusing. So, which should you choose?  

There’s also the question of experience. It stands to reason that the more you test, the better prepared one is for uncovering security vulnerabilities.

However, it's important to be aware of where your provider’s experience lies – does their background match up with what technologies you're using? They may have lots of testing know-how but if it’s not geared toward those particular applications then there could still be problems lurking.

You will ultimately gain the most benefit from a well-rounded approach. Above all, look for a team with proven expertise and a wide range of service options – your budget will go way further.

Offensive security qualifications are a good starting point, and there are specific Offsec qualifications for infrastructure, web application and wireless.

In the UK, Offsec qualifications are a good barometer, but you could also look for CREST-qualified individuals, same as in the US and ANZ. If you're looking for more senior testers, then you might want CCT-qualified individuals, and Infrastructure and Web Application CCT for each job.

Many organizations in the UK require CHECK Team Leaders/Members for their engagements, but this just unnecessarily narrows your scope of potential vendors. CHECK Team Leaders/Members still have CREST CCT or CRT, but they also have Security Clearance which you really only need if you’re working in central government or handling sensitive government data. If you’re a bank, you can just request CREST-qualified individuals and have clauses in your contract, including a background check if you want.

For more information, check out our guide to choosing a pentesting company.

Network penetration testing with Intruder

Intruder is a great way to get started with network penetration testing because you’ll get market-leading continuous vulnerability scanning in the process. We’re firm believers that it shouldn’t matter how big your business is or what your needs are: everyone deserves the same level of security. We help you secure your attack surface with features designed to dramatically simplify pen testing:

  • Continuous network scanning: every time you add something to the portal or make changes, we'll make sure it gets checked out right away and then keep monitoring at regular intervals so nothing slips through unnoticed.
  • Emerging threat scans: we keep a vigilant eye out for new threats to your sensitive data so at the first sign of danger, we sweep through all external targets with an emerging threat scan - just in case.
  • Rapid response: we detect potential risks before they have a chance to become an issue with manual scanning and continuously monitoring security threat feeds. When something pops up that we think could be affecting your system, we'll provide you with details on how best to protect yourself.

Network penetration testing doesn’t have to be complicated. Try Intruder today to see how easy it is to keep your network safe or choose a time to chat with us for more information.

Get our free

Ultimate Guide to Vulnerability Scanning

Learn everything you need to get started with vulnerability scanning and how to get the most out of your chosen product with our free PDF guide.

Sign up for your free 14-day trial

7 days free trial