Penetration testing, commonly referred to as ethical hacking, is the practice of rooting out any underlying security gaps within networks and wireless systems, application software, computers, and even employees. Depending on the project's objective, penetration testing can either be internal or external.

One of the most important reasons for conducting penetration testing is to allow an organisation's IT teams to determine the whys and hows of potential security break-ins and ways to prevent or reduce their effects. Moreover, penetration testing serves as a way to assess whether existing security policies are effective enough to combat the latest threats in the cybersecurity landscape. In a way, they can be likened to fire drills for organisations. With that said, what exactly separates internal and external penetration testing? Below, we outline what each entails and why both are equally important.

External pen testing

External penetration testing is a practice that focuses on an organisation's externally-facing assets to test its vulnerabilities and assess its risk of being targeted by remote attackers. Exploiting found vulnerabilities determines what kinds of information may be exposed to outsiders in the event of an attack.

The main goal of external pen testing is to simulate an actual threat actor conducting an attack on the internal work by leveraging the security gaps discovered on the externally-facing assets. This starts with open source reconnaissance, wherein the testing team uses publicly available resources to uncover sensitive information about the organisation, such as the technologies they use, potential employee usernames, and other relevant information that can be used later.

A vulnerability scan and full port scan then follow, which footprints the organisation's external perimeter and checks for easy-to-find weaknesses that could lead to a more significant exploit. Once done, manual and automated exploit attempts will commence and start searching for vulnerabilities missed by automated scans, exploit previously identified vulnerabilities, and determine the associated risks.

Internal pen testing

Unlike external pen testing, internal pen testing uses a distinct method of dealing with attacks and generally comes after an external pen test is completed. In this test, the main goal is to determine what an attacker can compromise or damage should they manage to gain internal access to the organisation's network.

The importance of internal pen tests lies in the fact that internal threats – including third-party vendors, careless or rogue employees, and malicious insiders, to name a few – are equally serious to external threats. Testing teams will test all available technologies used by the organisation, which could cover the following:

● Employees

● Workstations and mobile devices

● Firewalls

● Access points

● Wi-Fi networks

● Servers

● Internet-capable HVAC systems

● Cameras

● Intrusion Detection Systems (IDS) and Intrusion Prevention Systems (IPS)

After identifying the security weaknesses in these components, the team will exploit them to better understand the damage that unauthorised access could entail. Their findings will naturally be consolidated in a detailed report to allow the organisation to take the necessary actions and patch the vulnerabilities as soon as possible.

Internal pen tests can be done in many ways, from testing teams using privilege escalation, stealing credentials, spreading malware, and carrying out other malicious attacks, such as man-in-the-middle attacks. Some of the most common internal pen testing methods include:

● Port scanning

● Password strength testing

● Internal network scanning

● Firewall testing

● Database security controls testing

● Manual vulnerability testing

Conclusion

It is best practice for all organisations to conduct external and internal pen tests alongside periodic security audits to ensure the robustness of their cybersecurity posture and get an idea of what could be compromised in an attack. And if you’re seeking an accredited cybersecurity specialist, there are many things to look out for in a penetration testing service provider, such as their credentials. Hopefully, the contents above have provided sufficient insights into the inner workings of this indispensable component of the continuous need for better cybersecurity.

To ensure your organisation is always one step ahead of known and unknown threats, reach out to GROUP8 today and get access to our industry-leading offensive-inspired cybersecurity solutions. Our cybersecurity services include everything an organisation would need to strengthen its cybersecurity postures, such as CREST-certified penetration tests, vulnerability research, network security, incident response, blockchain security, and more. Contact us at hello@group8.co for more details.