Penetration testing, often referred to as pen testing, is a simulated cyberattack conducted by ethical hackers to identify vulnerabilities in an organisation’s systems, networks, or applications. The goal is to uncover weaknesses before malicious actors can exploit them, helping organisations strengthen their security posture and meet compliance requirements.
Unlike automated vulnerability scans, penetration testing mimics real-world attack scenarios, including phishing, credential theft, and lateral movement
How Penetration Testing Works
Penetration testing follows a structured methodology, typically broken down into the following phases:
1. Scoping and Planning
Define the systems, applications, and networks to be tested. This includes identifying constraints, business hours for testing, and any exclusions (e.g. no denial-of-service or social engineering)
2. Reconnaissance
Gather information about the target environment using passive and active techniques. This helps identify potential entry points and vulnerabilities
3. Scanning and Enumeration
Use tools to detect open ports, services, and software versions. Enumerate system details to build a map of the attack surface
4. Exploitation
Attempt to exploit identified vulnerabilities to gain unauthorised access or escalate privileges. This phase simulates what a real attacker might do
5. Post-Exploitation
Assess the depth of access and potential impact. Determine how far an attacker could go and what data or systems could be compromised
6. Reporting and Remediation
Deliver a detailed report outlining findings, risk levels, and remediation guidance. This includes technical descriptions and tactical recommendations
7. Retesting
Validate that vulnerabilities have been properly fixed and that the environment is now secure
Types of Penetration Testing
- External Pen Testing: Targets internet-facing systems like websites and email servers.
- Internal Pen Testing: Simulates an attacker who has breached the perimeter or a malicious insider.
- Web Application Testing: Focuses on client portals, case management systems, and APIs.
- Red Teaming: A full-scope simulation of advanced persistent threats (APT) using stealth and persistence.
- Objective-Based Testing: Tailored to specific business concerns, such as protecting sensitive legal data or demonstrating compliance
Why Penetration Testing Matters
Risk Reduction
Identifies exploitable weaknesses before they can be used in ransomware or data breach attacks.
Regulatory Compliance
Supports frameworks like ISO 27001, GDPR, Cyber Essentials Plus, and SRA Code of Conduct
Client Trust
Demonstrates due diligence in protecting sensitive data and builds confidence with stakeholders.
Security Validation
Ensures that implemented controls are effective and resilient against evolving threats
