Security Audit

What is External Pentest and How to Do It?

Updated on: February 20, 2024

What is External Pentest and How to Do It?

In today’s digital-first world, organizations are increasingly vulnerable to cyberattacks. In fact, according to a recent report by Cybersecurity Ventures, global cybercrime costs are projected to reach $10.2 trillion annually by 2025.

Such a rapid increase highlights the pressing importance for organizations like yours to use strong cybersecurity methods to keep their information safe and protect their valuable assets. This is where external penetration testing steps in. In this write-up, we will explore its applications and differences in techniques. So let’s get started!

Action Points

1. External Penetration Testing mimics real-world attacks, probing web, mobile, and network vulnerabilities.

2. Internal testing is in-house and costly, while external can be outsourced to independent researchers, is cost-effective, and provides a fresh perspective.

3. It involves five steps: pre-engagement, scope definition, exploitation, reporting, and remediation

4. Penetration testing is detailed, combining manual and automated methods, while cost-effective vulnerability scanning focuses on severity.

What is External Penetration Testing (EPT)?

External penetration testing is a security assessment that simulates the tactics and techniques of real-world attackers to identify and exploit vulnerabilities in an organization’s external systems and networks. It is conducted by an external security team that encompasses a detailed source code review, and manual inspections. 

Commonly, such external penetration testing is performed for web apps, mobile apps, network & network devices, and so on.

Note: Penetration testing of external systems – those accessible via the Internet – is also sometimes called external penetration testing. External systems usually include – web apps, networks, routers, switches, sub-domains, login systems, etc. This type of penetration testing is popularly known as Network penetration testing.

Internal vs External Pen testing

In the above context, there is another kind of penetration testing service – Internal penetration testing. Internal penetration testing, as you’d have guessed, is conducted by an in-house security team in an organization.

Internal and external penetration testing have their own benefits and limitations. You’ll understand them better by looking at their differences:

Type Internal Penetration Testing External Penetration Testing
1.Internal penetration testing is done by in-house security researchers. External penetration testing is done by an independent team of security researchers.
2.It can be costly to maintain a full-time security team.It is cost-effective to outsource security testing.
3.Since in-house security researchers know the ins & outs of a system, they often struggle to look at it from a hacker’s perspective.External penetration testing offers a fresh perspective on the system’s security and is great at emulating a hacker’s behavior on the target system.
4.Internal penetration testing requires less planning and can be done more frequently.Since it’s an outside engagement, it is time taking to conduct frequently. Check out this blog to get an idea of how much penetration testing costs.
5.Internal penetration testing does not suffice in compliance requirements.External penetration testing is necessary to comply with various compliances.
Difference between internal & external penetration testing

How to Perform an External Penetration Testing

Planning avoids chaos. To conduct a successful & systematic external penetration test you need to follow a process. Broadly speaking, external penetration testing can be broken down into five steps:

Stages in external penetration testing
Stages in external penetration testing

1. Pre-engagement:

This is the phase where the tester & the client decide on the terms of the engagement, pentesting methodology, types of tests, security objectives, & outcomes to avoid any mismatches.

To make the most of an external pentest, you (the client) must have answers to these questions ready:

  • Why do I need pentesting
  • What am I trying to achieve from it
  • Will I need additional tests
  • What approach I am looking at? Black-box, white-box, gray-box
  • What assets are crucial to my organization and should be prioritized
  • Do I have certification requirements, and so on.

Once you’ve everything working for you, you can flag off the penetration testing after closing the deal and signing an NDA (Non-disclosure agreements).

2. Scope defining or Reconnaissance

Scope defining is where you recognize your assets (web pages, user roles, APIs, networks, etc.) that would undergo the pentest. This is also the part where both the parties share necessary details & access.

It is generally during this step, security researchers & the organization decide on the type of penetration test to conduct.

For instance, if your organization needs its network to be tested, you may need network penetration testing, if you need to test your web app, you need web app pentesting, and so on. But since most organizations have a little more complex structure, you may likely need a combination of these tests to fulfill your security objectives.

3. Exploitation

Exploitation is the most exciting and important part of penetration testing. This is where pentesters try to penetrate your system with a series of attacks.

Your application or network is tested for attacks such as SQLi, privilege escalation, XSS, etc. Pentesters use some sophisticated tools to quicken some scanning activities during the test.

For example, our automated vulnerability scanner scans an application or network for 2500+ vulnerabilities. Some of them are shown in this picture:

Vulnerabilities flagged by Astra’s pentest scanner

Other than Astra’s pentest scanner, here are some tools (in no particular order) that come in handy during this process:

NOTE: The tests in this step vary from application to application. You may need to add/remove certain tools to cater to the unique requirements of an organization.

If you’re conducting penetration testing yourself, make sure you have all the necessary accesses, documented scope, and the right tools with you. Refer to these blog posts for detailed steps involved in manual penetration testing:

It is one small security loophole v/s your entire website or web application

Get your web app audited with Astra’s Continuous Pentest Solution

4. Reporting & Remediation

After the test, the tester documents the findings in a detailed yet crisp report. An ideal penetration testing report should contain details of the vulnerabilities, CVSS score, steps to reproduce, steps to fix, etc. A penetration testing report should also sum up the core insight of the report in a short & comprehensible summary that can be reviewed at a glance.

Here’s a sample report by Astra Security for your reference.

Coming to Remediation. This is where the organization needs to fix the reported vulnerabilities. Fixing the vulnerabilities well within the engagement’s validity will mean the tester will retest the deployed fixes. Failure to meet the deadline would require a new engagement or additional costs for the rescan.

Most pentesting reports provide fixing help, some pentesting companies like Astra Security even offer direct assistance to developers in fixing the vulnerabilities. Deploy those fixes and implement best security practices as suggested.

For example, at Astra, we share detailed steps to fix as well as a platform to ask doubts in our dashboard.

External penetration testing report
An example of vulnerability reporting by Astra Security
‘Steps to fix’ suggested by security researchers at Astra Security
Remediation collaboration & fixing assistance provided by Astra security researchers

5. Re-Scan & Certification

External penetration testing (EPT) ends with the penetration tester testing the fixes and best practices implemented by you. If the vulnerabilities are patched effectively, the security team/company will issue a pentest certificate to your organization.

Pentest certificate by Astra Security

What is the External Network Penetration Testing Checklist?

  1. Define the scope of the test, including the targets, applications, and systems to be assessed.
  2. Identify critical assets and sensitive data repositories within the organization’s network.
  3. Prioritize vulnerabilities based on their severity and potential impact.
  4. Attempt to exploit identified vulnerabilities using various attack techniques and tools.
  5. Provide clear and actionable recommendations for remediating the identified vulnerabilities.
  6. Maintain open communication with the organization’s IT team throughout the testing process.
  7. Avoid causing any disruption or damage to the organization’s systems during the testing process.
  8. Comply with all relevant laws, regulations, and ethical guidelines.
  9. Document all interactions and findings throughout the testing process.
  10. Prepare a comprehensive report detailing the findings of the penetration test, including identified vulnerabilities, exploited weaknesses, and potential security risks.

External Penetration Testing or Vulnerability Scanning?

When talking about penetration testing, another word that often comes up is ‘Vulnerability Scanning‘. Vulnerability Scanning (aka automated penetration testing) is the process of scanning your application with the help of security tools. It is primarily an automated process, barring the manual verification at the end of the scan.

Vulnerability scanning is quick to perform and is cost-effective. Here are some other differences between external penetration testing and vulnerability scanning:

Type External Penetration TestingVulnerability Scanning
1.Penetration testing is an evaluation of your current security status through a series of systematic manual & automated tests. Vulnerability Scanning is out and out an automated process that detects all possible exploitable surfaces in a system.
2.Penetration testing is a thorough process of identifying vulnerabilities and determining their impact. It involves the exploitation of vulnerabilities to see the complete picture.Vulnerability Scanning deals with just the basic inventory of vulnerabilities and does not involve exploitation to gauge impact.
3.Penetration testing is a complex and intricate process. One needs to have the proper education & experience to conduct it successfully.Vulnerability Scanning is easy and pretty straightforward to conduct. One can conduct vulnerability scanning with a basic idea of the right tools and steps.
4.Conducting penetration testing, that too external penetration testing is a time-taking affair, and can take several days to several weeks to complete. It’s harder to replicate the entire process every week, or on-demand so to say.Vulnerability Scanning takes a few seconds to a couple of minutes to complete. So, you can conduct vulnerability scanning regularly, without much planning & pain.
5.Since penetration testing involves long hours of manual effort and is high on human intelligence, it invariably costs more.Vulnerability Scanning is cost-effective.
6.The reporting in external penetration tests provides a detailed explanation of the vulnerabilities found, including proofs-of-concept, CVSS score, bug bounty loss, steps to reproduce & steps to fix.Vulnerability Scanning reports usually just list the vulnerabilities in order of severity, without going too deep into explaining each vulnerability.
Difference between external penetration testing & vulnerability scanning

Get an external pentest with Astra Security now

If you’re looking for in-depth, hassle-free external penetration testing, you’ve found one with Astra Security 🙂

Astra Security offers a thorough external penetration testing suite with over 8000+ tests – Manual and Automated. Astra Pentest provides an intuitive pentest dashboard that facilitates real-time vulnerability reporting, management & collaboration for each vulnerability, thus cutting the vulnerability fixing time for developers.

Here are a few features of the Astra Pentest:

  • Hacker-style penetration testing (with over 8000+ tests)
  • Developer-friendly intuitive dashboard
  • Real-time vulnerability reporting (first set of vulnerabilities added within 24 hours)
  • Direct collaboration (no email threads)
  • Vulnerability PoCs & selenium scripts
  • Fixing advice
  • Rescans
  • Detailed reports
  • Publicly verifiable certificates.

Also check out the new features added to our pentest dashboard.

Astra Security’s new pentest dashboard


In conclusion, external penetration testing is a vital security assessment to identify and address vulnerabilities in an organization’s external systems. It involves a detailed process, including pre-engagement, scope definition, exploitation, reporting, and re-scan. 

Moreover, it differs significantly from vulnerability scanning and internal pentesting in terms of depth, complexity, cost, and reporting comprehensiveness. So get your external scan today!


1. How long does an external pen test take?

An external pentest on average takes one to two weeks, with the exact length depending on various factors, including the size and complexity of the organization’s network, and the number of systems and applications to be tested.

2. How much does external penetration testing cost?

The cost of an external penetration test (EPT) can vary widely, ranging anywhere from $4,000 to $100,000. The final cost is dependent on various factors such as your organization’s size, complexity, specific testing requirements, and depth along with frequency.

Aakanchha Keshri

Aakanchha is a technical writer and a cybersecurity enthusiast. She is an avid reader, researcher, and an active contributor to our blog and the cybersecurity genre in general. To date, she has written over 200 blogs for more than 60 domains on topics ranging from technical to promotional. When she is not writing or researching she revels in a game or two of CS: GO.
Notify of

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Inline Feedbacks
View all comments

Psst! Hi there. We’re Astra.

We make security simple and hassle-free for thousands
of websites and businesses worldwide.

Our suite of security products include a vulnerability scanner, firewall, malware scanner and pentests to protect your site from the evil forces on the internet, even when you sleep.

earth spiders cards bugs spiders

Made with ❤️ in USA France India Germany