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What is an External Penetration Test?

As cybercrime continues evolving, the need to innovate new ways to protect sensitive information grows increasingly important. Cyberattacks cost businesses around $8 trillion globally, and that number is only increasing.

One of the best ways to analyze the strengths and weaknesses of your cybersecurity strategy is to run external penetration tests. External pen testing is a controlled attack that helps you identify areas for improvement.

In this guide, we take you through the basics of running an external penetration test and why we recommend it as part of your ongoing cybersecurity strategy.

What is an External Penetration Test?

An external penetration test is a simulated attack on your company’s perimeter systems.

It’s a security assessment designed as a controlled hacking attempt on external assets and networks accessible via the internet.

For example, an ethical hacker could run web application penetration using SQL injection or distributed denial of service (DDoS) techniques. One of the most reliable ways to check the security of your webapps and services is to mimic hackers’ techniques.

An external pen test is therefore considered a “dry run” to help businesses spot security flaws and weaknesses they need to address as a priority.

To demonstrate, we run external penetration testing services to:

  • Uncover successful attack methods
  • Assess how quickly it could take a hacker to access data
  • Test the strength of existing security controls
  • Investigate how far an attacker could get internally based on existing security controls
  • Make immediate security recommendations to tighten up the perimeter

External penetration testing can look different from client to client, depending on what is required. For example, during external pen tests, we might address the following areas of concern:

  • Software updates and patching
  • Configuration security
  • Authentication standards
  • Potential for data leakage
  • Encryption
  • Password practices
  • Network traffic management

How to Perform External Penetration Testing

Running an external penetration test takes careful vulnerability assessment and action planning. It’s wise to work with a managed security team who can safely handle the hack simulation for you. Otherwise, you could risk harming your network or its security without intending to.

We suggest an in-depth five-point action plan as follows:

1.   Discussion and planning

We work closely with the end client to decide the overall objectives of the test. Are there any specific areas or flaws that need particular attention?

2.   Scoping

Our ethical hacking team clearly defines which systems or assets are included in the scope of testing. For example, this might include assessing specific web pages, networks, apps, APIs, user accounts, IP addresses, or a firewall.

The testing team then tailors the assessment to utilize specific types of penetration testing techniques that will work best.

3.   Attacking

With the scope clear, we now “attack” your infrastructure and the agreed assets through various means. For example, controlled DDoS, SQL injection, and brute force attacks help us understand how strong a perimeter is and what data is accessible.

We may also analyze what’s accessible through phishing and social engineering.

4.   Reporting

Following the simulated attack, testers return to the client with a complete list of hacks attempted and any identified vulnerabilities. Reports show clients where action is recommended to help tighten network security, e.g., better password controls to safeguard against brute force attacks.

5.   Retesting

The process is repeated after fixes and upgrades are applied. Running a retest helps a penetration tester ascertain whether further recommendations are needed and ensures clients are safe.

Naturally, the exact scope of penetration testing plans and execution varies from case to case. However, the general idea is to perform regular scheduled testing and keep running attacks until security controls are hardened enough to guard against real-world threats.

Benefits of External Penetration Testing

External network penetration testing is an efficient and cost-effective way to analyze your security standards.

Let’s explore some of the wider benefits.

It gives a top-down view of vulnerabilities

Many businesses aren’t aware of security vulnerabilities until they’re breached. Effective penetration testing exposes these flaws so clients can take immediate action to fix them.

It’s a fresh perspective on your cybersecurity

It’s not always easy to measure the security strength of your own web application, and it’s always a good idea to get a second opinion. External pen testing’s independent perspective helps you see any flaws or issues you might miss.

It uses the same strategies as real-world hacking

External pen testing is designed to mimic typical hacking strategies used by cybercriminals. Therefore, the strategies used are highly accurate and reliable, removing the need for guesswork.

It helps to maintain compliance

Businesses that are accountable to regulators and government agencies must prove they’re secure and compliant with standards. This isn’t possible without hard evidence of testing and proof of remediation. External pen tests show regulators you’re compliant by exposing threats and taking preventive action.

It reduces cost

Without external pen testing, your company risks considerable financial impact from data breach events and dwindling business. System downtime (caused by attacks usually spotted in these tests) drives up expenses and pushes customers away.

What is the Difference Between External Penetration Testing and Vulnerability Scanning?

Vulnerability scanning examines networks and inspects assets for known common vulnerability signatures to identify and report weaknesses. External penetration testing takes the next step to directly attack an infrastructure after spotting security weaknesses in systems and networks.

Both options have benefits. External penetration is a largely manual testing process, meaning human testers always manage the attacks. That can be extremely useful when applying context to attack strategies and making security suggestions.

Vulnerability scanning, meanwhile, is a largely automated process. Think of it as somewhat similar to running a malware scan on a PC or Mac, but more thorough and specifically tuned to spot security weaknesses.

As an automated process, vulnerability scanning is faster and cheaper than external pen testing. That said, unlike pen tests, it’s entirely passive. It’s down to the client security team to further assess vulnerabilities. That can add time and effort – and without expert insight, relying on vulnerability scanning alone can leave you unaware of which weaknesses may actually be exploited.

That’s why we recommend using vulnerability scanning alongside external penetration testing. Vulnerability scans can help inform pen testers to an extent, and testers will explore broader and connected problems to make more reasoned, specific fix suggestions.

It’s the difference between just using a tool to find issues and delegating security testing to a team of human experts. It pays to invest in pen testing for the most thorough checks and recommendations.

External vs. Internal Penetration Testing

As their names suggest, external penetration tests occur outside an organization’s network, while internal tests occur inside. Crucially, the difference is all about perspective, and we always suggest running both.

Internal penetration testing:

  • Explores what real-world attackers can do if they gain access to an internal network
  • Addresses opportunities for potential malicious attacks by employees
  • Discovers problems that could be made worse through negligence

Internal pen testers assume the role of someone who might have broken into a system or who might be acting maliciously from the inside. However, internal pen testing only shows part of the security picture and doesn’t consider vulnerabilities from the view of an outside attacker.

That, however, is no excuse for avoiding one in favor of the other. It’s important to conduct internal security reviews to identify and mitigate potential vulnerabilities for in-house processes, systems, and practices. External testing is essential to ensure that any entry points into your infrastructure are fortified. Both investigations work together to help you build a more reliable security posture.


How Long Does an External Pen Test Take?

An external pen test can take days or up to several weeks to complete, depending on the size and scale of a system infrastructure. It also varies depending on specific attacks requested and agreed upon in preliminary meetings. The more requirements and assets there are, the longer the process will likely take.

How Much Does External Penetration Testing Cost?

The final cost of an external penetration project depends on the complexity and scope of the simulation and whether you choose to run any further tests after completion. Budgeting is typically discussed in the early fact-finding stages of a project.


Knowing how secure your data and assets are in an ever-changing threat landscape is vital.

Therefore, one of the most reliable ways to gain this insight is to run external penetration tests alongside internal checks.

At VikingCloud, we provide a complete 360-degree fortification against evolving threats and malicious attacks.

From vulnerability scanning to internal and external pen tests and assessment of incident response practices, we dive deep to help you keep your perimeter robust and reliable.

Reach out for a discovery call to find out more, and let’s start testing your security inside and out!



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Andrea Sugden
Chief Sales and Customer Relationship Officer

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