What Do You Need to Know About External Network Penetration Testing?

Every modern organization heavily relies on external networks that provide access to servers, web applications, APIs, and other critical stuff. However, these networks are often the primary targets for cybercriminals. Why? Open ports, outdated software, and weak passwords all create numerous opportunities for attacks.

To mitigate these exposes to danger, organizations conduct External Network Penetration Testing, which helps identify vulnerabilities and assess real threats. 

In this article, we will explore how External Network Penetration Testing works, the stages involved in the process, and how it helps businesses enhance their cybersecurity posture.

What is External Network Penetration Testing?

External Network Penetration Testing is the process of assessing the security of a company's external infrastructure. This involves gaining an understanding of the current state of cybersecurity and providing recommendations for improving protection. 

The goal is to identify vulnerabilities that could be exploited by cybercriminals to gain unauthorized access to the organization’s credentials. As an example can be misconfigured firewall, outdated software, open ports, weak passwords, and more.

The following info will be evaluated by the pentester team during this test:

• public IP addresses, 
• web application servers, 
• mail servers,
• VPN and DNS systems, 
• firewalls, 
• open ports and services,
• web services and APIs, 
• remote management, 
• Internet of Things (IoT), 
• cloud infrastructure, 
• SSL/TLS certificates, 
• version control systems.

Checking these resources allows you to reveal vulnerabilities and ensure comprehensive protection of the organization from external threats.

7 Benefits of External Network Penetration Testing for Business

External Network Penetration evaluation is critical for every organization that relies on internet resources, as it helps reveal and eliminate vulnerabilities before malicious actors can exploit them.

Key benefits of the external network penetration test:

1. Protection against external threats. Identifies vulnerabilities accessible via the internet (open ports, weak passwords) and prevents cyberattacks that could lead to data breaches or loss of control over systems.
2. Competitive advantage: building trust. Companies that demonstrate a high level of threat management are more likely to be chosen by clients and partners. External Network Penetration Test shows that an establishment actively cares about its security.
3. Preservation of data privacy. Prevents the leakage of sensitive data, such as customer personal info, financial info, or intellectual property.
4. Cost optimization and the reduced downtime. Early identification of vulnerabilities ensures the smooth operation of external services and helps avoid costs associated with addressing the aftermath of attacks: downtime, system recovery, fines, or lawsuits.
5. Regulatory compliance. Adhering to security requirements, such as PCI DSS, GDPR, ISO 27001, HIPAA, etc., during an external network penetration test helps avoid fines or penalties for non-compliance.
6. Improved overall cybersecurity. Assessing the current security state of external infrastructure and providing recommendations for addressing identified vulnerabilities helps prevent their recurrence in the future.
7. Preparedness for attacks and increased awareness. Test fosters a deeper understanding of the organization's network and its weak points. Being prepared for potential penetrations enables better protection and assessment of resilience against threats.

External Network Penetration check is an integral part of any company's security strategy. It helps minimize risks, protect assets, comply with standards, and strengthen brand trust.

Duration of the process and frequency of external network penetration testing

Usually, the external network penetration testing process takes from 3 to 14 business days. The pentest duration depends on the following factors:

• Size and complexity of the infrastructure.
• Type of the test: manual or automatic.
• The choice of test tools and methods.
• The depth and result of the analysis.
• Other features.

Companies often customize test timelines to meet specific client requirements, striking a balance between speed and depth of the penetration test.

External network penetration analysis should be conducted regularly and at key points in the development or changes in the organization's setup. The frequency is influenced by factors such as the level of risk in the industry, the amount of change, and the activity of threats.

Our pentesters have recommended frequency of pentest:

• Annually: to ensure a basic level of security. This is the minimum recommendation for most companies.
• Semi-annually: for organizations that process sensitive databases (e.g., in the financial and healthcare industries) or have a high risk of attack.
• Every time:

• • After system upgrades or changes: adding new servers, updating software, changing network configuration;
  • before important events: launching a new website, mobile application or other web public service;
  • after cyber incidents: if the company has already become a victim of an attack.

Regular test is a compliance with standards and an investment in security that avoids significant financial and reputational losses.

What are the main approaches to External Network Penetration Testing?

When performing external network penetration testing, the pentesters team usually uses two main approaches: Black-Box and Grey-Box Testing. Each has its advantages and is chosen depending on the purpose of the test and the information provided.

Black-Box 

With this approach, the pentesters have limited or no information about the organization. Pentesters just start to act like external hackers, trying to find and utilize vulnerabilities without access to internal documentation or systems. Testers work only with publicly available assets (IP addresses, domains, open ports).

Advantages:

• Effectively simulates real breaches, as the tester is in conditions similar to those in which an attacker would operate.
• Helps to scan critical vulnerabilities that can be exploited from the outside.

Usage:

• When you need to check how the organization looks from the point of view of a potential attacker on the internet.
• If the company wants to keep its facilities secure, even for the testers team.

Gray-Box 

This is essentially a combination of Black-and-White Testing that takes into account the advantages of both approaches. Gray Test strikes a balance between the realism of attack simulation and the depth of analysis.

Advantages:

• More realistic attack simulation.
• Provides sufficient depth of analysis.
• Saves time and budget.

Usage:

• When you need a balanced approach to depth and realism: This is usually required by every medium or large organization.
• If there are budget constraints: You want to conduct effective assessment, but without the high cost of a full web audit.
• Partial trust: You're willing to provide some information to pentesters, but don't want to disclose all the details of your internal setup.

White vulnerability testing is usually used by pentesters to test an internal network.

7 Main stages of the External Network Penetration Testing process

External Network Penetration Testing includes the following main steps:

1. Information Gathering

The process starts with studying the scope of testing and obtaining by pentesters the necessary permissions, as well as identifying the network foundation and collecting technical details. 

At this stage, information about the organization available on the internet is collected to help pentesters understand which organization assets are accessible from the outside and can be potential targets of attacks. 

Testers team can use the following methods:

• Pentesters can use OSINT (Open Source Intelligence).
• Analysis of public records such as DNS, WHOIS, and IP addresses.
• Search for subdomains, SSL certificates, corporate contacts.

2. Reconnaissance

To identify possible penetration testing points and understand how the external infrastructure is configured, security specialists conduct a detailed study of the target network and its assets:

• Scanning for open ports and active features.
• Collects information about software versions.
• Determining hosts accessible via IP addresses.

At the reconnaissance stage, pentesting tools such as Nmap, Netcat, and Masscan can be used.

3. Discovery and Scanning

This step includes automated and manual vulnerability scanning to identify vulnerabilities, analyze configurations of all servers, open ports, outdated software, and test cloud or APIs within a specified timeframe. Pen testers can use the following vulnerability detecting tools: Nessus, OpenVAS, Qualys, Burp Suite.

4. Vulnerability Assessment

Next, you need to understand which vulnerabilities are the most dangerous and prepare a plan for their exploitation. This is done by analyzing the vulnerabilities found: determining the potential impact on the establishment and categorizing vulnerabilities by risk level (low, medium, high, critical).

5. Exploitation

To determine how vulnerable the website is to real attacks and what data can be accessed, pentesters at this stage attempt to exploit the vulnerabilities found to penetrate the system. They test weak passwords or incorrectly configured services, conduct attacks through open ports, using tools such as Metasploit, Hydra, SQLmap, Burp Suite.

6. Final Analysis and Report findings

After the test, you need to provide the customer with a clear understanding of the security level of the network and a step-by-step plan for improving it — a pentesting report. For this purpose, the following is carried out:

• Evaluation of the findings, which includes analyzing the potential impact of the identified vulnerabilities and developing recommendations to address the problems found.
• Preparation of a report — documenting every vulnerability found, conclusions about risks and remediation methods.

7. Utilize the Test Results

To ensure real improvements in network security and reduce the risk of threats in the future, it is imperative to complete the last standard step of the pentest process:

• Implement the recommendations in the pentest report. For example, update outdated software, correct web servers and network configurations, and implement a security policy.
• Verify the pentest findings: conduct retest after making changes and training employees on secure computing. Make sure that the deficiencies are fixed.

These 7 steps form a systematic approach to External Network Penetration Test.

What determines the cost of External Network Penetration Testing?

The cost of penetration assessment for external networks depends on many factors. Here are the main aspects that affect the service price formation:

• the scope, 
• complexity of the task, 
• depth of analysis.

The number and type of vulnerabilities detected, the level of access to information, the number of IP addresses, the use of automated or manual analysis, and the involvement of additional assets are all taken into account in the price. The level of experience of specialists, tight deadlines, industry and region specifics also matter.

When planning a pen test, it is important to clearly define organization scope in order to find the optimal balance between the quality of the service and its price.

Conclusion

Protecting external networks is a critical element of any company's cybersecurity. External Network Penetration Test allows you to identify weaknesses within the scope before they are exploited by hackers, ensuring the security of your info. Regular network penetration test not only help to avoid attacks, but also increases the trust of customers and partners.

Entrust the security of your network to professionals — order an external network penetration test at DATAMI and receive a detailed report with advices on how to improve your security. 

Contact us for a consultation today!