External Network Penetration Testing

What is an external network penetration test?

An external network penetration test or infrastructure penetration test is a security assessment of an organisation’s perimeter systems with the intention of highlighting vulnerabilities resulting from outdated software or various misconfigurations.

There are three forms of methodologies that can be used in external penetration testing; black box, grey box, and white box. 

Black box testing is when the pen tester has no prior information about the organisation’s infrastructure or data, and starts from square one, as hackers do. 

Grey box testing (or Gray box testing) is a penetration testing technique utilised to test a software product or application with partial knowledge of the internal structure of the application.

White box testing is when the pen tester is provided with all required information, in the case of an external penetration test it would be a list of the IP addresses that the client owns and wishes to be assessed.

External network penetration testing is often white box, however there are cases where a client will ask for the pen tester to see if they can find the IP addresses they own, which would be considered a black box assessment. The tester would then need to confirm the IP addresses are correct with the client before any scanning starts. For a grey box assessment, the client might provide a range of IP addresses, and have the tester confirm which ones in the range they think are relevant. Again, the tester would then need to confirm the IP addresses are correct with the client before any scanning can commence.

The Importance of Securing External Networks

In the digital age, as businesses and organisations increasingly rely on online platforms and services, the security of external networks has become a critical concern. External networks, which connect an organisation to the wider internet and other external entities, are often the first line of defence against cyber threats. Neglecting their security can have dire consequences. Here’s a deep dive into the importance of securing external networks.

1. Protection from Cyberattacks

External networks are frequently targeted by cybercriminals. Attacks such as Distributed Denial of Service (DDoS) can overwhelm a network, making services unavailable to users. By securing external networks, organisations can mitigate the risk of such debilitating attacks.

2. Guarding Sensitive Data

Many organisations handle sensitive data, be it customer information, financial records, or proprietary business data. External networks are gateways through which cybercriminals can access this data. Ensuring robust security measures are in place is crucial to prevent data breaches.

3. Maintaining Business Reputation

A security breach can severely tarnish an organisation’s reputation. Customers and partners expect their data and services to be safe. A compromised external network can erode trust, leading to loss of business and a damaged brand image.

4. Regulatory Compliance

In many regions, including the UK, there are stringent regulations governing data protection and cybersecurity. Organisations are required to take adequate measures to secure their networks. Failing to do so can result in hefty fines and legal consequences.

5. Ensuring Service Availability

A secure external network ensures that online services remain available to users. Any disruption, whether due to a cyberattack or a security flaw, can lead to financial losses and customer dissatisfaction.

6. Avoiding Financial Repercussions

Beyond regulatory fines, a security breach can have other financial implications. This includes the cost of remediation, potential lawsuits, and loss of business. Investing in external network security can prevent these unforeseen expenses.

7. Building and Maintaining Trust

For many businesses, especially those operating online, customer trust is paramount. A secure external network is a testament to an organisation’s commitment to safeguarding user data and providing reliable services.

8. Staying Ahead of Evolving Threats

The cyber threat landscape is constantly evolving, with new vulnerabilities and attack vectors emerging regularly. By prioritising external network security, organisations can stay abreast of these developments and implement timely protective measures.

What is the difference between an external penetration test and a vulnerability scan?

An external network pen test differs from a vulnerability scan as it offers the addition of manual testing. Using both disciplines minimises the potential for false positives, and covers areas that scanners are unable to discover.

For example, a scanner may note a port as being open but be unable to provide further information as it’s based on signature detection. Manual probing may allow for a penetration tester to identify a service that a scanner would have otherwise missed.

How is an external network penetration test performed?

Here at Aardwolf Security, our team of penetration testing experts have established an effective 6-step system external network penetration testing methodology.

    1. Reconnaissance

To get an idea of the client’s security level, a pen testing expert will first conduct an analysis, assessing the potential requirements, using Open Source Intelligence (OSINT).

    2. Scanning

Using automated scanners, the consultant will delve deeper into the infrastructure of the client’s servers scanning all 65535 ports, probing for services, their subsequent versions, and whether there are any associated misconfiguration.

    3. Manual assessment

This step is where most of the consultant’s time is utilised. Use a range of probing and verification techniques to delve deeper into the infrastructure, this process involves a range of specific manual penetration testing on the following areas: 

• Authentication
• Authorisation
• Session management
• Input validation and sanitisation
• Server configuration
• Encryption
• Information leakage
• Application workflow
• Application logic

    4. Exploitation

Next, the vulnerabilities unveiled in the scanning and manual probing stages are raised to the client. Depending on the client’s business operations and the severity of the vulnerabilities, the client may give the consultant the go-ahead to subject certain issues to exploitation attempts.

    5. Reporting

After the exploitation attempts have been made, the pen testing consultant will produce a comprehensive report to highlight the impact likelihood of all system defects, and recommend solutions.

    6. Retesting

The sixth and final step of the process, offered exclusively at Aardwolf Security, is a free retesting, once the client has actioned their software system solutions, to make sure that their infrastructure weaknesses have been resolved correctly and completely.

How long does it take to perform an external network penetration test?

There are numerous factors that influence the scoping of a penetration test, such as:

• The size of the subnet
• Underlying infrastructure
• Number of exposed services

Factors Influencing the Duration and Cost of an External Network Penetration Test

The duration and cost of these tests can vary significantly based on several factors. Here’s a closer look.

1. Scope of the Test

The broader the scope, the longer and more costly the test will be. If an organisation wishes to test only specific systems or applications, the duration and cost might be lower. Conversely, a comprehensive test of the entire network will require more time and resources.

2. Complexity of the Network

A complex network with multiple servers, applications, and devices will take longer to test than a simpler one. The presence of legacy systems, intricate configurations, or custom applications can also add to the complexity.

3. Depth of the Test

Penetration tests can range from basic vulnerability scans to deep, manual tests. The deeper the test, the more thorough the analysis, leading to a longer duration and higher cost.

4. Expertise of the Testing Team

A highly skilled team might command a higher fee but could potentially complete the test more efficiently. On the other hand, a less experienced team might charge less but take longer, potentially missing critical vulnerabilities.

5. Remediation and Retesting

If vulnerabilities are found and the organisation decides to fix them immediately, the testing team might need to conduct retests. This additional step can increase both the duration and cost.

6. Regulatory Requirements

Certain industries in the UK, such as finance or healthcare, might have specific regulatory standards for penetration testing. Meeting these standards can influence the depth, methodology, and consequently, the duration and cost of the test.

7. Use of Automated Tools vs Manual Testing

While automated tools can quickly scan and identify known vulnerabilities, manual testing is essential for uncovering more subtle, complex issues. A test that relies heavily on manual techniques might be more time-consuming but also more thorough.

8. Frequency of Testing

Some organisations opt for periodic tests, while others might choose continuous monitoring. Continuous testing can be more costly upfront but might lead to long-term savings by identifying and addressing vulnerabilities more promptly.

How much is external network penetration testing?

An external network pen test cost is calculated by the number of days a penetration tester will take to fulfil the agreed scope. The number of days can be determined by filling out our penetration testing scoping form or messaging us through our contact form to arrange a scoping call with one of our senior penetration testers.

What are the deliverables following an external pen test assessment?

Following the completion of external network penetration testing, the security consultants will produce a custom report highlighting any identified issues, their risk levels, and recommendations regarding how to remedy them.

Aardwolf Security utilise CREST accredited penetration testers for network penetration testing. With decades of collective experience in the field, SMEs all around the world put their trust in us to help them protect their business against cybercrime. 

If you’re curious as to how we could help reinforce your infrastructure, get in touch today to speak with one of our Senior Consultants, or fill out our 5-minute online quote form for a bespoke quote.