What is an Internal Penetration Test, and How is it Done?

Regrettably, cybercrime can occur from inside and outside your network. To block threats, you need more than a strong perimeter – you also need a robust internal security posture to protect against attacks through social engineering, phishing, and password theft.

Conducting an internal penetration test allows you to evaluate the security of your infrastructure by orchestrating a controlled and ethical breach. This type of testing enables you to uncover hidden security vulnerabilities and identify poor practices that could potentially be exploited by cybercriminals to compromise your network and access sensitive data.

Below, we explain what an internal network penetration test offers, how to get started, and why our team recommends regular tests for the most reliable security.

What is an Internal Penetration Test?

An internal penetration test is a controlled attack on your inner network and security strategy.

It’s a security measure that emulates what hackers or threat actors could do if they gain access to your infrastructure.

For example, internal pen tests analyze potential threats and damage caused through:

• Social engineering
• Password theft
• Phishing
• User attacks

During a controlled internal pen test, an ethical hacker might discover:

• Poor encryption practices
• Weaknesses in access and ID controls
• Low password security (e.g., single-factor authentication)
• Outdated software or security protocols
• Accidental system misconfiguration
• Evidence of intentional internal damage

A complete internal penetration test confirms that security controls are implemented and utilized according to best practices and any compliance requirements (e.g., PCI DSS). It also provides insight into the current security knowledge and threat awareness of your employees.

This type of penetration testing helps clarify the purpose of penetration testing by identifying where software upgrades, security policies, or staff training may need improvement

However, it’s worth remembering that internal pen testing can differ from one case to another. Our penetration testing services, for example, analyze your specific needs before launching attacks.

Who Conducts Penetration Tests?

Ethical hackers, such as those employed by managed security services providers, conduct penetration tests on behalf of businesses.

Businesses often hire external consultants such as VikingCloud to provide an outside perspective on their internal security measures.

Skilled penetration testers and ethical hackers have real-world hacking experience and skills but use their knowledge for good. Their abilities are essential for simulating cyberattacks and understanding potential unauthorized access.

Ethical hackers and security consultants help business owners find security vulnerabilities and areas of concern they might otherwise miss and build hyper-accurate threat models to real-world trends.

Internal pen testers are up to speed on the latest hacking techniques and exploits and think creatively and critically about the challenges a business’ infrastructure might face.

What Are the Top Penetration Testing Techniques?

Some of the most effective internal penetration testing techniques we use include:

• Brute-force attacks (password guessing with tools)
• Privilege escalation
• Database controls testing
• Man-in-the-middle attacks
• Phishing emails and social engineering (to access internal networks)
• Communication eavesdropping (through poisoning protocols and analyzing traffic)
• Inspecting internal accounts for sensitive information
• Port scanning
• Testing hardware vulnerabilities (e.g., through routers, IoT devices, workstations, printers)
• Testing software vulnerabilities (e.g., through operating systems, outdated programs)

Pen testers also use various testing tools to carry out custom-controlled attacks. These can include resources such as Wireshark, which analyzes traffic, and Nmap, a port scanner.

The most valuable internal penetration testing techniques emulate those used by successful cybercriminals.

Internal pen techniques are frequently organized into three categories:

• Black Box
• White Box
• Gray Box

Black Box pen testing is “blind” in that testers work in practice environments without access to sensitive data, which can be time-consuming. Meanwhile, White Box tests provide more detail to hackers – useful data such as schematics, IP addresses / IPs, and source code are available.

Gray Box tests take a middle ground – a tester works with a privileged user to access systems and work “live.”

For the most accurate and effective penetration testing, Viking Cloud uses “live” techniques, which help our testers access information to assist with vulnerability assessments.

Internal Penetration Testing Steps

We advise breaking internal penetration testing into six key steps: planning and preparation, information gathering, vulnerability assessment, exploitation, documentation, and vulnerability resolution.

Here’s how we typically carry out each stage

1. Planning and Preparation

We start by defining the project's scope. Are there any specific areas of the client’s network our testers should focus on?

We carefully establish a penetration testing methodology, attack vectors, rules, and objectives. For example, the test may be to test password strength.

2. Information Gathering

The team gathers crucial information about target networks and systems impacted by the attack. This helps our experts to ascertain which tools and strategies to use during the data breach.

Testers may also build maps of the client network and infrastructure to work on during the exploitation phase.

3. Vulnerability Assessment

Testers attempt to break into the internal network using methods predetermined with the client. This can include social engineering, brute-force attacks, and cross-site scripting (or XSS).

Upon breaching security, testers note areas of vulnerability and concern ready for controlled exploitation. These details are also recorded for the client’s knowledge at the end of the attack.

4. Exploitation

Testers now exploit the vulnerabilities they find with tools and current hacking techniques. This stage gives our team useful information on how long it takes to break certain protocols, and how difficult it is to access sensitive data and/or take control.

5. Documentation

Testers document all vulnerabilities and exploitation results, successes and failures. These details help us to build a clear analysis and tailor an action plan to the client.

6. Vulnerability Resolution and Remediation

After the attack, our security experts break down a full analysis of what testers discovered (e.g., identified vulnerabilities) and what they achieved.

This helps us advise on effective security controls and risk mitigation to improve the client’s information security management.

Benefits of Internal Pen Tests

Internal penetration testing helps you see how secure your infrastructure is through the eyes of a hacker.

From the inside, it can be difficult to accurately tell how secure your network and hardware are until it’s too late. Internal pen testing effectively brings that worst-case scenario forward in a controlled and safe testing environment.

It is a “rehearsal” to help fortify your defenses should a legitimate attack occur.

Internal pen testing:

• Prevents a loss of money and reputation in the long run
• Gives you a fresh perspective on your existing protocols and training standards
• Satisfy testing obligations for compliance standards and legal requirements
• Puts your network infrastructure through a rigorous, comprehensive analysis
• Offers a top-down view of your network’s security flaws

Internal vs. External Penetration Testing

An external penetration test is a manual security assessment that takes place outside a network.

During the process, hackers and security consultants analyze potential vulnerabilities in your infrastructure’s perimeter.

For example, an external pen tester may test your web application or website security and ascertain how quickly and easily they can access your systems via the internet.

Internal penetration testing, meanwhile, analyzes what hackers are potentially able to do once inside your network. This type of security testing also accounts for potential malicious attacks from inside a company or client base.

External pen testers take up the role of a hacker trying to break in from the outside, while internal pen testers play the part of someone who’s already got access.

We recommend running both types of penetration tests to build a complete picture of infrastructure security. Although informative, purely running internal pen tests don’t account for how hackers access networks in the first place.

Running internal and external reviews helps to boost your overall security posture. With the support of security analysts and ethical hackers, you can ensure entry points are fortified and that your internal processes and practices are robust against any successful attackers.

Conclusion

Big data is constantly growing, and with it, malicious insider threats to your sensitive information are increasing. A simple firewall and occasional vulnerability scanning cannot protect your data in the modern cybersecurity landscape.

One of the best ways to test your infrastructure and network security is to beat hackers at their own game – and try out their techniques in a safe, controlled test.

At VikingCloud, we offer internal and external penetration testing to safeguard clients from malicious attacks inside and out.

Don’t assume your internal and external defenses are up to scratch until you run pen tests – and partner with a consulting security team with years of experience in protection and recovery.

Book a discovery call with us today, and let’s start setting up a security action plan.