For many organisations, the idea of a penetration test sounds slightly intimidating.
Questions usually follow fairly quickly:
Will it disrupt the business?
Could systems go offline?
What are testers actually doing?
How do we know it is being carried out safely?
These are fair concerns.
After all, you are effectively inviting a cyber security company to simulate an attack against your systems.
At Securebytes, we believe a good infrastructure penetration test should never feel chaotic, risky, or mysterious. It should feel structured, methodical, professional, and importantly, safe.
In this article, we explain what actually happens during an infrastructure penetration test, how the process works, and what you should expect from a professional CREST-accredited provider.
First Things First: What Is an Infrastructure Penetration Test?
An infrastructure penetration test assesses the security of internal and external systems, networks, servers, firewalls, cloud-hosted services, remote access solutions, wireless networks, and supporting infrastructure.
Put simply, it answers an important question:
“If somebody attempted to compromise our environment, what could they realistically achieve?”
Unlike vulnerability scanning, which focuses on identifying known weaknesses, a penetration test validates exploitability and demonstrates real-world risk.
The goal is not simply to identify issues.
It is to understand how an attacker may chain weaknesses together, move through the environment, escalate privileges, or gain access to sensitive systems and data.
Step One: The Scoping Call
A good penetration test starts long before testing begins.
The first step is usually a scoping call.
This is one of the most important stages of the engagement because it ensures the assessment is designed around your organisation, infrastructure, and objectives.
No two environments are identical.
During the scoping discussion, we typically cover things such as:
- What systems are in scope
- Internal, external, wireless or cloud testing requirements
- Critical systems or operational constraints
- Objectives and concerns
- Existing security tooling and monitoring
- Preferred testing windows or restrictions
- Whether authenticated or unauthenticated testing is required
This stage helps define expectations and avoids surprises later.
It also ensures the test remains focused, efficient, and aligned with risk.
Sometimes organisations approach testing with a broad goal such as:
“We want to know how secure we are.”
The scoping process helps turn that into something practical and measurable.
Step Two: Rules of Engagement and Formal Sign-Off
Before testing begins, we hold a Rules of Engagement discussion and obtain formal approval.
This is effectively the agreement that defines how testing will be conducted.
It covers:
- Scope and authorised targets
- Testing windows
- Emergency contacts
- Restrictions or exclusions
- Approved testing methods
- Communications throughout the engagement
Nothing happens until sign-off is complete.
This protects both parties and ensures testing is transparent, controlled, and formally authorised.
A professional penetration test should never feel like someone simply “starts scanning” and hopes for the best.
Why CREST Matters
Not all penetration testing providers are equal. At Securebytes, infrastructure penetration testing is delivered by CREST-certified professionals using structured methodologies and recognised best practice.
Being CREST-certified means testing is carried out against recognised standards, with appropriate governance, quality assurance, professionalism, and technical competence. That matters because penetration testing is not simply about running tools. It is about knowing when to stop, how to assess impact safely, how to validate findings correctly, and how to avoid introducing unnecessary risk to production systems.
The difference between a professional tester and someone running automated tooling becomes very obvious when systems are critical to business operations.
Internal Testing: Why We Test as Both an Attacker and an Authenticated User
One area people are often surprised by is how internal penetration testing works.
At Securebytes, we normally assess environments from multiple perspectives.
Unauthenticated Internal Testing
First, we test from the perspective of a threat actor with access to the internal network.
Such as:
- A rogue device plugged into a network port
- A malicious insider
- An attacker with physical access
- A compromised guest network scenario
This helps us understand what somebody could do with network access but without credentials.
Could they enumerate systems?
Access services?
Capture credentials?
Move laterally?
Reach sensitive systems?
Authenticated Internal Testing
We also commonly perform authenticated testing.
This simulates scenarios such as:
- A phished user account
- Stolen or breached credentials
- A rogue employee
- An attacker who already has a foothold in the environment
Why does this matter? Because many real-world attacks do not begin with full administrator access. They begin with a single compromised user account.
Testing from an authenticated position allows us to assess privilege escalation paths, access controls, segmentation, excessive permissions, and opportunities for lateral movement.
In simple terms:
“If somebody compromises a normal user, what happens next?”
That question is often far more valuable than organisations expect.
Can Infrastructure Penetration Testing Be Done Remotely?
Yes. In many cases, infrastructure penetration testing can be delivered remotely through the deployment of an on-site testing appliance. Where required, Securebytes can provide a secure testing box that is connected within your environment and used to conduct internal testing remotely. This approach is particularly useful for organisations with multiple locations, operational constraints, or environments where on-site attendance is unnecessary.
Is Penetration Testing Safe?
This is probably the biggest concern we hear. And rightly so. The answer is:
Yes — when performed properly.
Professional penetration testing should be controlled, measured, and methodical. At Securebytes, testing is performed carefully to minimise operational risk while still providing meaningful security assurance. Where alerts or detections occur, we validate them.
Where possible, we verify whether defensive controls identified our activity. If our actions are detected, that is useful validation for your monitoring capability.
If they are not detected? That is important too. Because the uncomfortable reality is simple:
If your security team cannot see a penetration tester, there is a good chance they would not see a real attacker either.
This becomes particularly valuable for organisations investing in SIEM, MDR, Microsoft Sentinel, Huntress, SOC monitoring, or wider detection and response capability. Testing should not only identify vulnerabilities. It should also help validate visibility.
The Outcome: Practical, Real-World Security Insight
A good penetration test is not simply a list of technical findings.
It should help organisations understand:
- What an attacker could realistically do
- Where risk exists
- What should be prioritised
- Which controls worked
- Which controls failed
- How security posture can be improved
Most importantly, findings should be validated, contextualised, and practical to remediate.
TLDR
Infrastructure penetration testing should not feel disruptive, unpredictable, or risky.
When delivered correctly, it is a structured, controlled process designed to improve confidence in your security posture while identifying meaningful risk.
At Securebytes, our approach is professional, methodical, CREST-aligned, and designed to provide practical outcomes without unnecessary complexity.
If you are considering an infrastructure penetration test, whether internal, external, authenticated, unauthenticated, remote, or on-site, speak to the team.
We are always happy to have a straightforward conversation about how testing works and what would be most appropriate for your environment.