Penetration testing helps businesses identify vulnerabilities, misconfigurations, and security risks within their IT systems. By simulating real-world cyberattacks, ethical hackers can uncover weaknesses before malicious actors exploit them. As cyber threats become more advanced, regular penetration testing has become a critical part of any strong security program.
This guide will explore the various penetration testing strategies, why they are important for businesses, and how they can align with your compliance and security requirements.
Why Penetration Testing Matters
No business wants to discover a security flaw the hard way. Conducting penetration tests allows businesses to detect and address security gaps before an attack occurs. These tests are invaluable for:
- Identifying Security Vulnerabilities Before Attackers Do—Regular testing helps pinpoint weaknesses in firewalls, applications, networks, and internal processes, allowing companies to address risks before hackers exploit them.
- Meeting Compliance Requirements—Many security frameworks, such as SOC, PCI, ISO 27001, and CIS, require or recommend penetration testing. For example, in a SOC 2 audit, proof of recent testing and remediation shows a business’s commitment to security.
- Enhancing Risk Management – Businesses in highly regulated industries, such as finance and healthcare, face significant consequences in the event of a breach. Identifying vulnerabilities can help prevent sensitive data loss, financial penalties, and damage to your reputation.
Key Components of a Penetration Test
A thorough penetration test typically consists of four primary phases:
- Planning & Reconnaissance – Defining the scope and objectives of the test while collecting information on the target systems, including domain registrations, network configurations, and software components.
- Scanning & Vulnerability Assessment – Using automated tools and manual testing to identify weaknesses such as open ports, unpatched software, and poorly managed user permissions.
- Exploitation & Post-Exploitation – Attempt to exploit identified vulnerabilities to assess real-world risks, including sensitive data exfiltration, privilege escalation, or lateral movement within the environment.
- Reporting & Remediation – Provide a full report outlining all the vulnerabilities, potential attack paths, and recommended mitigation strategies.
Types of Penetration Tests
Penetration tests can take different approaches, depending on the level of information available to testers. Understanding the distinctions between the different methods helps businesses choose the most effective strategy.
White Box Penetration Testing
White box testing gives testers full system knowledge, including source code, network diagrams, and configuration details. This approach is ideal for assessing code integrity, evaluating security controls, and uncovering vulnerabilities in complex internal workflows. Because testers don’t need to spend time on reconnaissance, they can focus on in-depth analysis and remediation.
Example: Think of white box testing as a fire safety inspector that was able to gain access to a building’s blueprints, allowing them to easily check every emergency exit, wiring system, and structural weak point.
Black Box Penetration Testing
In contrast, black box testing simulates a real-world attack scenario in which testers have no prior knowledge of the system. They must conduct reconnaissance, probe network boundaries, and identify exploitable vulnerabilities just as an external attacker would.
Example: Black box testing is similar to a thief attempting to break into a building without knowing its layout—it tests how well security measures can withstand an unknown threat.
Grey Box Penetration Testing
Grey box testing is a hybrid approach in which testers receive limited knowledge about the system, such as user credentials or network architecture details. This approach balances depth and realism, making it a practical and efficient testing method and our primary service offering.
Example: Think of grey box testing as an undercover security consultant with partial access to a business, testing for vulnerabilities from insider and outsider perspectives.
Internal vs. External Penetration Testing
In addition to choosing a testing strategy, businesses should determine whether internal or external testing is most relevant to their security objectives.
- Internal Network Penetration Testing – Focuses on threats from within the business, such as an employee misusing access or an attacker who has breached the perimeter.
- External Network Penetration Testing – Targets internet-facing assets, such as web applications, cloud services, and network endpoints, to assess how well the business’s perimeter security holds up against external attacks.
Social Engineering and Other Specialized Tests
Technical security controls are only part of the equation—human factors also play a critical role in cybersecurity. Social engineering tests evaluate how susceptible employees are to phishing, pretexting, and other tactics used by attackers.
John Pohlman, Senior IT Consultant at Tanner, notes:
“In many penetration tests, we find that technical defenses are strong, but a single well-crafted phishing email can bypass them. That’s why testing human factors is as critical as testing firewalls and applications.”
Common Challenges and Lessons Learned
While penetration testing provides significant security benefits, businesses often face common challenges, including:
- Keeping the Scope Up to Date – As IT environments evolve, new systems, cloud services, or integrations may introduce vulnerabilities not presented in previous tests.
- Overcoming Testing Obstacles – Intrusion detection systems, endpoint protection, and other security measures can sometimes interfere with testing, requiring careful coordination with security teams.
- Effective Remediation – A penetration test is only valuable if the identified vulnerabilities are fixed. Detailed documentation and follow-up testing ensure security gaps are closed.
Penetration Testing for Compliance
Regulatory frameworks such as SOC, PCI, ISO, and CIS emphasize the need for ongoing vulnerability management. Well-documented penetration testing efforts can serve as critical evidence of compliance. For example:
- SOC 2 Audits – Require evidence that security controls are both designed effectively and actively maintained.
- PCI DSS – Requires testing the Cardholder Data Environment (CDE) on a regular basis to verify cardholder data cannot be leaked.
- CIS – Specifically includes penetration testing as a recommended practice for assessing network and application security.
Maintaining a consistent testing schedule and documenting remediation efforts can strengthen a business’s security posture while simplifying compliance reviews.
Choosing the Right Penetration Testing Provider
Selecting a qualified penetration testing firm is crucial. Businesses should evaluate:
- Expertise – Does the provider specialize in the technologies and frameworks relevant to your business?
- Testing Approach – White box, black box, or grey box—what methodology aligns with your security goals?
- Post-Test Support – The testing team will offer remediation guidance and retesting to confirm the vulnerabilities were fixed.
A thorough assessment of a provider’s experience and methodology ensures a high-quality engagement that delivers actionable security insights.
Strengthening Security Post-Test
After a penetration test, businesses should take the following steps to reinforce security:
- Prioritize Remediation – Address critical vulnerabilities first and makes sure long-term fixes are implemented.
- Communicate Findings – Share test results with key stakeholders, including IT, development, and leadership teams.
- Enhance Security Awareness – Conduct training sessions to improve employee awareness of threats such as phishing and social engineering.
- Schedule Follow-Up Testing – A retest of previously identified vulnerabilities will make sure that security gaps are fully resolved.
Tanner Security Penetration Testing Services
Penetration testing is a crucial part of any cybersecurity strategy. Whether using white box, black box, grey box, internal, or external testing, businesses can identify vulnerabilities before they lead to security incidents. A well-planned testing program, combined with timely remediation, reinforces defenses, supports compliance, and maximizes the effectiveness of cybersecurity investments against evolving threats.
The Tanner Security team would love to talk with you about your penetration testing journey. Please let us know if there is anything we can do for you to support your IT security program. Contact us at your earliest convenience to schedule a free penetration test consultation.