What is Penetration Testing?

What is Penetration Testing?

Penetration testing (pen testing) is a controlled, simulated cyberattack conducted by security professionals to identify vulnerabilities and weaknesses in an organization's systems, networks, and applications before malicious actors can exploit them. Unlike automated vulnerability scanning, penetration testing involves manual techniques, creative thinking, and the ability to chain multiple findings together to demonstrate real-world attack scenarios.

Types of penetration testing

Penetration tests are categorized by scope and approach:

By target:

• External testing — targets internet-facing assets such as web applications, APIs, email servers, and firewalls
• Internal testing — simulates an attacker who has gained access to the internal network
• Web application testing — focuses specifically on web application vulnerabilities (injection, authentication flaws, etc.)
• API testing — evaluates the security of application programming interfaces
• Mobile application testing — assesses mobile apps for security weaknesses
• Wireless testing — tests wireless network security
• Social engineering — tests human vulnerabilities through phishing, pretexting, or physical access attempts

By knowledge level:

• Black box — the tester has no prior knowledge of the target environment, simulating an external attacker
• White box — the tester has full access to source code, architecture documentation, and credentials
• Gray box — the tester has partial knowledge, such as user-level credentials or limited documentation

The penetration testing process

A professional penetration test follows a structured methodology:

1. Scoping — define the targets, objectives, rules of engagement, and testing window
2. Reconnaissance — gather information about the target through passive and active techniques
3. Vulnerability identification — discover potential weaknesses using automated tools and manual analysis
4. Exploitation — attempt to exploit identified vulnerabilities to demonstrate real-world impact
5. Post-exploitation — if access is gained, assess how far an attacker could go (lateral movement, data access, privilege escalation)
6. Reporting — document all findings with severity ratings, evidence, and remediation recommendations
7. Remediation support — assist the organization in understanding and addressing findings
8. Retest — verify that remediation efforts have effectively addressed the vulnerabilities

Penetration testing in compliance frameworks

Multiple frameworks require or recommend penetration testing:

• SOC 2 — while not explicitly mandated, penetration testing supports CC7.1 (detection of vulnerabilities) and CC4.1 (monitoring)
• PCI DSS — Requirement 11.4 requires annual penetration testing of the CDE, plus testing after significant changes
• NIST CSF — DE.CM (continuous monitoring) and ID.RA (risk assessment) are supported by penetration testing
• ISO 27001 — control A.8.8 addresses management of technical vulnerabilities, which penetration testing supports

Frequency and timing

• Annual testing is the minimum standard for most compliance frameworks
• After significant changes — major infrastructure changes, application releases, or acquisitions should trigger additional testing
• Continuous testing programs — some organizations implement bug bounty programs or periodic testing throughout the year

Selecting a penetration testing firm

When choosing a penetration testing provider:

• Look for relevant certifications (OSCP, OSCE, CREST, GPEN)
• Request sample reports to evaluate reporting quality
• Verify the firm carries appropriate insurance
• Confirm experience with your technology stack and industry
• Ensure clear rules of engagement and communication protocols

How episki helps

episki tracks penetration testing schedules, stores reports, and manages remediation of identified findings. The platform links pen test results to compliance framework requirements and monitors remediation progress. Learn more on our compliance platform.