Penetration testing is a crucial component of any organisation’s security strategy. With many different types of penetration testing – spanning approaches, scopes, and methodologies – it can be challenging to determine which is right for your business.
Different systems face different risks, and not every pentest uncovers the same vulnerabilities. This guide breaks down the main types of penetration testing, when to use them, and how to choose the right approach for your security goals and compliance requirements.
Black box vs white box vs grey box penetration testing
A key decision when considering types of pentesting is how much information you provide to testers. The level of insight directly affects accuracy, realism, and the types of vulnerabilities discovered.
Two types of penetration testing are black box (no info) and white box (full info).
Black box penetration testing
- No internal information provided (no credentials, diagrams, or system access)
- Simulates an external attacker starting from your public footprint
- Ideal for assessing real-world exposure and perimeter weaknesses
- Answers: What can an outsider discover about your systems?
White box penetration testing
- Full system visibility: documentation, architecture, source code, credentials
- Enables deep analysis of internal logic, architecture, and hidden flaws
- Best for organisations wanting extensive, detailed coverage
- Helps identify issues before an attacker ever sees them
Grey box penetration testing
- Partial information provided (e.g., user credentials, high-level architecture)
- Balances realism and efficiency
- Delivers thorough results without the effort of full white box testing
Penetration testing types overview
| Penetration test type | Threats addressed | Compliance requirements |
| Internal network | Insider threats, lateral movement, privilege escalation | ISO 27001, SOC 2 |
| External network | Internet-facing attacks, perimeter weaknesses | PCI DSS, ISO 27001 |
| Web application | SQLi, XSS, auth flaws, logic errors | PCI DSS, OWASP Top 10 |
| Mobile application | Insecure storage, weak APIs, session issues | GDPR, industry-specific |
| Social engineering | Phishing, pretexting, physical impersonation | ISO 27001, security awareness |
| Wireless network | Rogue APs, weak encryption, unauthorised access | PCI DSS, ISO 27001 |
| Cloud | Misconfigurations, IAM issues, exposed resources | SOC 2, ISO 27001 |
| Physical | Tailgating, device planting, unauthorised access | Industry-specific |
| API | Broken auth, data exposure, injection flaws | OWASP API Security Top 10 |
Types of penetration testing: Deep dive
Network penetration testing
Network penetration testing uncovers weaknesses in infrastructure, such as open ports, misconfigurations, insecure services, outdated systems, or poor segmentation.
It evaluates the security of:
- Routers, firewalls, switches
- Servers and operating systems
- Network segmentation
- Access controls
For organisations with complex IT environments, network pentesting is a foundational security measure.
Internal infrastructure vs external infrastructure
External infrastructure penetration testing:
- Targets internet-facing systems (websites, firewalls, VPNs)
- Simulates attackers probing perimeter defences
- Answers: What can be discovered from the public internet?
Internal infrastructure penetration testing:
- Assumes an attacker already has network access
- Evaluates lateral movement, privilege escalation, and breach containment
- Models phishing, malware, or insider threats
Most organisations require both: external testing protects your perimeter, while internal testing reveals what happens after that perimeter is breached.
Read more: What is the difference between internal vs external penetration testing?
Web application penetration testing: Testing your software and web apps
Web application penetration testing analyses the security of custom or commercial applications. It focuses on:
- Authentication and session management
- Access control
- Input validation
- Injection vulnerabilities (SQLi, XSS)
- Business logic flaws
- Issues aligned with OWASP Top 10
Testers assess how applications handle data, enforce permissions, and protect sensitive information.
Why it matters
Web apps often manage high-value data – customer records, payment details, or business-critical operations. Their constant exposure makes them prime targets, making this one of the most important test types for many organisations.
Mobile application penetration testing: iOS and Android security
Mobile application penetration testing tests unique risks across device-side storage, APIs, and backend integrations. Testing typically covers:
- Insecure local storage
- Weak encryption
- Authentication and session flaws
- API security gaps
- Certificate validation
- Reverse engineering risks
Why it matters
As mobile-first business models grow, this testing is essential for protecting user data and complying with regulations such as GDPR. High-risk industries (finance, healthcare, retail) should prioritise mobile security.
Read more: The importance of mobile application penetration testing services
Social engineering testing: The human element
Social engineering penetration testing targets people rather than systems. This testing includes:
- Phishing simulations
- Vishing (voice phishing)
- Pretexting
- Physical social engineering (e.g., impersonation attempts)
Why it matters
Attackers frequently exploit human trust, not just technical flaws. Social engineering tests measure how effectively employees recognise and respond to manipulation attempts, helping organisations strengthen their ‘human firewall.’
Wireless network testing: WiFi and network security
Wireless penetration testing examines:
- WiFi access point configuration
- Encryption standards
- Rogue devices
- Network segmentation
- Default or weak credentials
Common risks include outdated protocols (e.g., WEP), unauthorised access points, or guest networks that allow internal access.
Why it matters
Physical proximity makes wireless networks attractive targets. Offices, warehouses, retail, and hospitality environments benefit greatly from wireless security assessments.
Cloud penetration testing: AWS, Azure, and cloud security
Cloud environments create new attack surfaces, especially around:
- IAM roles and policies
- Misconfigured services
- Public storage buckets
- Unsecured endpoints
- Network segmentation within cloud platforms
Misconfigurations remain the leading cause of cloud breaches.
Why it matters
As organisations move to hybrid and multi-cloud architectures, cloud penetration testing becomes essential for preventing costly misconfigurations and data exposure.
Physical penetration testing: On-site security assessment
Physical penetration testing assesses the strength of onsite security controls through real-world attempts to access restricted areas.
Testers may attempt:
- Tailgating
- Lock bypassing
- Badge cloning
- Planting malicious devices
- Accessing unattended workstations
Why it matters
Industries like finance, healthcare, government, and data centres require strong physical controls. A physical breach can undermine even the strongest cybersecurity measures.
API penetration testing: Securing your integrations
APIs connect modern applications and are a frequent target for attackers. API pentesting assesses:
- Authentication and authorisation
- Rate limiting
- Input validation
- Data exposure
- Object-level and function-level access issues
- Injection attacks
Common vulnerabilities include BOLA (Broken Object Level Authorisation) and excessive data exposure.
Why it matters
With microservices and integrations increasingly central to business operations, API penetration testing is vital to prevent data leaks, account takeover, or abuse of functionality.
Automated vs manual penetration testing
Both automated and manual penetration testing play important – but different – roles in a business’s security strategy.
Automated penetration testing:
- Uses scanners and tools to quickly detect common issues
- Ideal for ongoing vulnerability management
- Pros: Fast, wide coverage
- Cons: Cannot identify logic flaws or multi-step attack chains
- Conducted by skilled pentesters
- Identifies complex vulnerabilities that automation misses
- Pros: Real-world attacker mindset, deeper insights
- Cons: More time-intensive and costly
Most organisations benefit from a hybrid penetration testing approach: automation for continuous scanning, manual testing for high-risk or complex systems.
Point-in-time vs continuous penetration testing
How often you test depends on your environment’s pace of change and risk tolerance.
Point-in-time penetration testing:
- A single assessment at a specific moment
- Often used for compliance, new releases, or annual audits
- Provides a snapshot of your security posture
- Suitable for stable environments
- Required by PCI DSS, ISO 27001, SOC 2, and other frameworks
Continuous penetration testing:
- Ongoing or frequent assessments
- Ideal for agile teams and fast-paced development
- Ensures new features, assets, and changes remain secure
- Reduces the risk between annual tests
Organisations deploying code weekly or daily usually prefer continuous testing.
How to choose the best type of penetration testing for your needs
Selecting the right pentesting type depends on several factors:
Industry and compliance requirements
Industry standards often dictate required testing:
- PCI DSS – annual network and application tests
- ISO 27001 – regular assessments
- SOC 2 – ongoing security monitoring
Understanding your compliance landscape helps identify which tests you need to do.
Company size and complexity
Larger organisations with diverse tech stacks typically require multi-layer testing – internal and external networks, web and mobile apps, cloud infrastructure, and APIs.
Smaller companies may focus on their most high-impact systems first, and expand coverage as budgets allow.
Level of risk
Risk-based prioritisation focuses testing efforts on what matters most:
- Which systems would cause the most damage if compromised?
- Which are most attractive to attackers?
- Which have the greatest business impact?
Prioritising based on risk (rather than count) ensures your resources are allocated effectively
Budget
Budget constraints are a reality for most security teams. A risk-based approach also ensures you’re investing in pentests that target:
- Systems with sensitive data
- Revenue-generating services
- Public-facing assets
Testing frequency
How often you test should align with how often your environment changes:
- Fast-moving teams = continuous testing
- Stable environments = annual or quarterly testing
OnSecurity: Your one-stop penetration testing platform
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With flexible options, free retests, and a consultative approach, OnSecurity ensures every security investment turns into measurable risk reduction.
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