Cyber Security
Internal vs. External Pentests

Internal vs. External Pentest – Why Both Are Important?

Nowadays, with technological evolution, external threats are also increasing. Therefore, organizations need to have robust and secure IT infrastructure. When organizations suffer from a security breach, they pay massive financial costs. So, the best approach is to perform internal and external pentest to identify security vulnerabilities and address them as soon as possible. 

In this article, we’ll compare internal vs. external pentest and find out why both are important. So, let’s start. 

Internal and External Pentest – Why Do You Need Both?

Organizations need to understand the value of internal and external Pentest to choose a pen test that suits their needs. Attacks can come from internally and externally; therefore, it’s essential to understand weaknesses. 

What Is Internal Penetration Testing and Why It’s Important?

People who have direct access to the organization’s data can cause an internal threat. Even people who’re aware of cyber-attacks are prone to mistakes. Moreover, organizations don’t know what is entering or leaving their networks. A faulty configuration makes the entire network vulnerable to attack. So, if your external pen testing is secure, you still need internal pen testing. 

Don’t allow your employees to connect their USBs to your organization’s systems. They can use it to insert malware. With an internal pen test, you can quickly identify which areas attackers can target to gain access to confidential information. 

When to Perform Internal Penetration Testing?

Internal pen testing can help if:

  • Your infrastructure is insecure
  • Your organization has been the victim of an internal attack before
  • Your employees aren’t well aware of cyber-attacks and can lead to the spread of malware.  

What Is External Penetration Testing and Why It’s Important? 

These tests identify programs with external access. For example, a firewall, IoT device, web application, or server can be accessed publicly. Hackers can target e-mail, website, or file sharing to gain access to sensitive data of an organization. 

For example, a file-sharing system without a password can put your organization at risk. Every employee doesn’t need access to files, so when everyone has access to it, it makes your confidential data vulnerable to attacks. Similarly, messaging platforms can also make your organization vulnerable to attacks. 

Therefore, files should be password encrypted, and messages should also be encrypted so that only people with passwords can access these files and messages. 

When to Perform External Penetration Testing?

External pen testing can help if:

  • You have recently launched public-facing FTP servers, applications, and websites.
  • You’re looking to improve security because your organization recently had a data breach.
  • You have done routine vulnerability scans and found that your website and application are vulnerable to external threats.

Internal vs. External Pentest

The main difference between internal and external penetration testing is the type of attack they’re tested for. As the name indicates, an internal penetration test assesses internal networks to identify vulnerabilities. Business partners or malicious employees can exploit these vulnerabilities internally. 

Another use of internal Pentest is identifying the potential malware spread by employees within internal systems. Now you might wonder how internal penetration testing is performed. In internal penetration testing, the tester has the same access that an employee in an organization has. It helps testers determine how much damage a malicious employee can cause by spreading malware or an internal attack. 

Internal penetration testing includes man-in-the-middle attacks, monitoring, malware spreading, personal data leakage, and any other malicious attack. On the other hand, external penetration testing identifies security vulnerabilities that attackers can exploit on public networks. For example, they can exploit networks used by a website or application. 

There can be various targeted areas that need to be tested during external Pentest, such as file-sharing systems, messaging platforms, and other administrative features. These vulnerabilities allow attackers to exploit confidential information. Depending on the complexity of a network or application, it can take a few days to weeks to perform external Pentest. 

Difference between Internal and External Pentest 

Let’s differentiate between the two in a table form. This table can help you understand the pros and cons of internal and external Pentest. 

Internal Penetration Test External Penetration Test
Vulnerabilities are identified from the internal attacker’s point of view. Vulnerabilities are identified from an external attacker’s point of view.
It’s an excellent way of ensuring security. It requires planning and is often done a few times only. 
It requires an in-house security team, so it’s expensive.  It doesn’t require an in-house security team, and outsourcing can be done that makes it cost-effective. 
It’s comprehensive because the attacker can exploit both internal and external systems.  It’s less comprehensive because you only need to assess and prevent external threats. 
It identifies the spread of malware by an internal employee.  Areas that need to be tested are file sharing and messaging platforms. 


We can conclude that both internal and external Pen tests are essential. Both have some differences, and you need to identify your business needs to choose the required penetration testing for your organization.

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