What is penetration testing in cybersecurity?
Penetration testing is an authorized, simulated attack on your own systems, carried out by a security professional to find out what a real attacker could reach. The tester tries to exploit weaknesses and chain them together, then reports each finding with evidence and the fix, proving which vulnerabilities matter in a way a scan alone cannot.
Penetration Testing is an authorized, simulated attack against a company's systems, applications, or staff, carried out by security professionals to find weaknesses that a real attacker could use. Unlike an automated scan, a penetration test involves a person attempting to chain findings together and reach something valuable, then documenting exactly how they did it and what would have stopped them.
Tests are scoped by target. An external test looks at what is reachable from the internet: the public website, email infrastructure, VPN gateways, and cloud services, along with information about the company and its staff that is publicly available. An internal test assumes the attacker already has a foothold and measures how far they can move. Application and source code tests examine custom software for flaws such as injection, broken authentication, or insecure data handling. Social engineering tests measure how staff respond to phishing. The deliverable is a report that ranks each finding by severity, with evidence and specific remediation steps.
For a small or mid-sized business a penetration test answers a question no policy document can: what would happen if someone tried? It surfaces the forgotten server and the shared password that nobody thought to mention. Cyber insurance carriers and enterprise customers increasingly ask for test results, as do frameworks such as PCI DSS and SOC 2. The scope should match the business; a company with a public website and Microsoft 365 needs a different test than one that ships its own software.
The free assessment is a remote external penetration test, limited to the information available to NetSys and the external scope we agree with you. A Tier 2 source code penetration test examines an application in an isolated sandbox and is quoted per codebase. The free offer does not include internal systems or onsite work. Details of both tiers are on the penetration testing service page.
Types of penetration testing
| What the tester attacks | The question it answers | At NetSys | |
|---|---|---|---|
| External network | Internet-facing systems: website, email, VPN, remote access and cloud services | What can an outsider reach from the internet? | Tier 1: free, remote, within an agreed external scope |
| Internal network | The office network, from a foothold such as a phished laptop or a rogue device | How far could an attacker move once inside? | Scoped separately |
| Web application | An application's logins, user roles, forms and APIs | Can one user reach another user's data or take over the app? | Tested in Tier 2 when the source code is provided; otherwise scoped separately |
| Source code | The code itself, built and run in an isolated sandbox, plus its dependencies and secrets | What would an attacker break with the code in hand? | Tier 2: quoted per codebase, under NDA |
| Social engineering | Staff, through phishing emails or pretext phone calls | Would someone hand over access? | Phishing simulations run through security awareness training |
| Wireless | Office Wi-Fi and the devices on it | Can someone nearby get onto the network? | Scoped separately |
Why it matters for a small business
Every owner believes their systems are reasonably secure until someone shows them a screenshot of their own customer database opened from the outside. A penetration test replaces belief with evidence. It tells you which defenses hold and what an attacker would go after first, in the order you should fix them. For a small business the external test is the place to start, because the internet-facing systems are the ones attackers scan constantly. A free first test removes the usual excuse for never having done one, and the report gives you a concrete list to hand to whoever manages your IT.
Penetration Testing: FAQs
What is penetration testing in cyber security?
Penetration testing is a controlled attack on your own systems, performed with permission by security professionals, to find vulnerabilities that could be exploited. Testers use the same techniques criminals use, from scanning and password attacks to phishing, but they stop short of causing damage and instead document what they found and how to fix it. Tests can target external systems, the internal network, web applications, source code, or employees, and the scope is agreed before work begins.
What is the difference between penetration testing and a vulnerability assessment?
A vulnerability assessment uses automated scanning, plus an analyst's review, to list and rank known weaknesses, such as missing patches or open ports, across many systems quickly. A penetration test is a person actively trying to exploit weaknesses and chain them together to reach sensitive data, then explaining the real-world impact. Assessments should run continuously or on a schedule; penetration tests are periodic and deeper. An assessment might report that a server is missing a patch, while a test shows that the missing patch let the tester read the payroll folder.
How much does a penetration test cost for a small business?
Cost depends on the agreed scope. NetSys offers a free remote external penetration test limited to information available to NetSys and agreed external scope. Internal reviews and Tier 2 source code testing are scoped separately; the source code test is quoted per codebase.
What are the types of penetration testing?
The main types are external network, internal network, web application, source code, social engineering and wireless tests. Each is defined by what the tester attacks: internet-facing systems, the office network from inside, an application's logic, its code, your staff or your Wi-Fi. Most small businesses start externally, then test where their own risk sits.
What are the phases of a penetration test?
NIST's testing guide, SP 800-115, describes four phases. Planning agrees the scope and rules of engagement in writing. Discovery maps the systems and finds weaknesses. Attack tries to exploit them and chain them together. Reporting documents each finding with evidence and the fix. A retest after remediation confirms the fixes held.
What is the difference between a penetration test and a red team exercise?
A penetration test tries to find and prove as many exploitable weaknesses as possible within an agreed scope and time, and the people who run the systems usually know it is happening. A red team exercise is a longer, goal-based simulation of a real adversary, such as reaching the finance system undetected, that also tests whether monitoring and staff notice and respond; few people are told in advance. Most small businesses need penetration testing first.
More terms
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