Have you ever been told your business needs a network penetration test but nobody’s ever explained what one actually is? This blog post breaks down one of the most commonly recommended cyber security tests in business. Read what actually happens during a test and how it fits into your wider security strategy.
What is a Network Pen Test?
Network penetration testing is a controlled, ethical hacking exercise in which a security specialist attempts to break into your network the same way a real attacker would. Network testing typically covers two angles:
Internal network testing: This sort of simulation is used to assess whether someone with stolen credentials or an employee within the organisation could access private or sensitive data.
External network testing: This type of simulation mimics an attacker attempting to break into the network from outside the organisation. This could include servers, apps, and websites that are classified as open-source risks.
Tools Used During Network Penetration Testing
Network penetration testers use a range of tools to discover systems, identify weaknesses and validate how an attacker could move through a network.
- CrackMapExec / NetExec – Used heavily for Windows and Active Directory enumeration and credential testing.
- Nmap – Used for host discovery, service detection and port scanning.
- Impacket – A collection of tools for interacting with Windows protocols such as SMB and Kerberos.
- BloodHound – Maps Active Directory relationships and potential privilege escalation paths.
- Responder – Tests weaknesses in local network authentication, including NTLM.
- Metasploit – Used to validate and safely exploit known vulnerabilities.
- Wireshark – Analyses network traffic and supports packet sniffing.
- Nessus – Identifies known vulnerabilities and configuration weaknesses.
- enum4linux-ng – Enumerates Windows and Samba users, groups, shares and policies.
- Hashcat – Tests the strength of recovered password hashes.
The tools used depend on the environment, but the real value lies in how an experienced tester interprets and combines the results.
Common Network Penetration Testing Scenarios
No two internal networks are exactly the same, but the same weaknesses tend to recur. We asked our penetration testers which attack paths they most commonly uncover during Internal Infrastructure Assessments. These are some of the scenarios they regularly encounter before digging into the finer technical detail:
- LLMNR/NBT-NS Poisoning > NTLM Relay – Legacy name-resolution protocols can expose NTLM authentication, allowing credentials to be relayed to other systems where signing or channel protections are weak.
- AD CS ESC8 > Domain Compromise – Misconfigured Active Directory Certificate Services web enrolment can allow NTLM relay attacks that result in certificate issuance and, in severe cases, domain-level compromise.
- Exposed SMB Shares > Credential Discovery – Tools such as Snaffler can identify passwords, API keys, configuration files and other secrets stored within accessible SMB shares, which may enable lateral movement or privilege escalation.
- Kerberoasting > Privileged Account Access – Weak service account passwords can allow attackers to extract Kerberos service tickets and attempt offline password cracking.
- Weak Local Administrator Controls > Lateral Movement – Reused local administrator credentials or poor credential separation can allow a compromised workstation to become a route into additional systems.
- Excessive Active Directory Permissions > Domain Escalation – Misconfigured group memberships, delegation or ACLs can create unintended attack paths from a standard user account to highly privileged domain access.
What Is Network Penetration Testing In Practice?
A network penetration test is a professional cyber security test that can last a few days to a couple of weeks. During the test, a pentester actively probes and attempts to exploit weaknesses in your network security.
The tester looks for known and unknown weaknesses, and then tries to exploit the meaningful ones to demonstrate a real-world cyber attack. A report is produced showing exactly what was found and what to fix first to improve network security.
If you want the full methodology we follow (scoping, reconnaissance, scanning, threat modelling, exploitation, and reporting), it’s detailed on our network penetration testing service page.
What Is Penetration Testing in Network Security?
Penetration testing as a whole is the “active” layer of assurance. It goes hand in hand with firewalls, monitoring tools, and vulnerability scanners, but it does a different job.
Some people tend to confuse penetration tests with vulnerability scans, but they’re not the same kind of test:
- A vulnerability scan is mostly just an automated scan. It checks your systems against a database of known issues and provides a list of potential issues.
- A penetration test goes much further. A human tester takes that list and their own research and actually tries to exploit what they find, chaining weaknesses together the way a real attacker would. This identifies which issues are high risk, including those that may not seem important but, when combined, can prove critical.
In other words, a vulnerability scan tells you what might be a problem. A penetration test tells you what actually is one and how bad it could get if nobody fixed it.
Other Types of Penetration Testing
Penetration testing is a broad term covering many branches of pen tests, and network testing is just one example. Some businesses often need more than one type depending on their circumstances:
- Web application testing focuses on the security of a website or web app, covering things such as login flows, session handling, and input validation rather than the network it runs on.
- API testing focuses on the interfaces your systems use to talk to each other. This could be authentication, authorisation, or data handling between services.
- Mobile application testing assesses iOS and Android apps, including how they store and transmit data on the device.
- Cloud security testing assesses the configuration of platforms like AWS or Azure. A different discipline from testing a traditional on-premises network.
- Social engineering tests your people and processes rather than your technology. Think phishing simulations and impersonation attempts. Much like real-world scammers.
Many organisations tend to combine a network test with one or two of the above. An example would be a business with both office infrastructure and a customer-facing web app. They might need network testing and web application testing. Not one instead of the other. If you’re not sure which combination applies to you, a VAPT (vulnerability assessment and penetration testing) engagement is often a broader starting point.
Conduct a network penetration test with Sencode.
Leaving your network security to guesswork is an incredibly risky strategy. A proper network pen test replaces that anxiety with clear facts, giving you a definitive list of what needs fixing. Our CREST-accredited testers will safely put your network through its paces and show you exactly how to lock it down. Get in touch with Sencode today for a fixed-price quote.