What Is Penetration Testing?
Penetration testing, also known as pen test, is an authorized and simulated cyber attack performed on an IT system (or systems) to evaluate existing security controls. In a pen test, an organization’s IT team allows an expert group of ethical attackers to try and compromise the organization’s security.
This authorization can include permission to:
- Access or escalate accounts or permissions through unauthorized means
- Install simulated malware
- Modify system configurations
- Demonstrate the ability to exfiltrate data or disrupt business operations
A pen test should never be performed by the team maintaining and defending the system being tested. In most cases, a pen test is performed by third-party experts who know how to attack systems.
Typically, a pen test will be a surprise to the security team. This ensures the test simulates real-world attack conditions, where the defenders will not have advance notice of attacker actions.
Penetration testing attempts to replicate the types of attacks that cybercriminals actually use. This means that a pen test goes much further than other assessments and exercises meant to identify risk.
What Are the Phases of Penetration Testing?
A pen test includes seven key phases, all of which follow the standard attack chain that would occur during a real-world cyber incident.
These phases are:
- Pre-engagement
- Reconnaissance or intelligence gathering
- Scanning and discovery
- Vulnerability assessment: Gaining access
- Exploitation: Maintaining access
- Post-exploitation, reporting, and risk analysis
- Remediation
What are the Benefits of a Pen Test?
Pen tests offer organizations a number of benefits, all designed around helping an organization understand their own cyber risk, security maturity, and cyber defenses.
Benefits include:
- Validation of Security Controls. Pen tests can help confirm whether existing defenses, configurations, and monitoring tools are working as intended under attack conditions.
- Risk Remediation Prioritization. Pen tests can provide IT and security teams with actionable insights into which vulnerabilities within their security architecture pose the greatest business risk.
- Identification of Real-World Vulnerabilities. Pen tests go beyond automated scans by simulating how attackers would exploit known vulnerability weaknesses within a system, application, or network.
- The Meeting of Compliance Regulation Requirements. Pen tests often meet regulatory frameworks (e.g., PCI DSS, HIPAA, ISO 27001) that require regular security assessments for participating organizations to stay compliant.
- Enhanced Incident Response (IR) Readiness. Pen tests are an opportunity to work through how well security and IT teams detect, contain, and respond to simulated attacks, as well as if a given organization’s IR plan works in action.
- Supported Strategic Security Planning. Pen tests provide leadership with data-driven insights to guide investment in security tools, processes, and training.
The Value of Pen Tests Results
The results of a penetration test should include both areas of success and defined areas for improvement, along with a detailed account of the methods the pen tester exploited to compromise your systems.
After a penetration test, an organization should gather stakeholders to review the test’s outcome. The review should cast a wide net — effective cybersecurity is a cross-functional exercise focused on business risk, not just IT threats alone.
An important stakeholder to include in this work is the IT team, including any security partners. When the pen testers can collaborate with a security team on a testing exercise and on a review of the resulting reports, they typically produce a more effective total understanding of an organization’s security.
How Organizations Should Respond to a Pen Test
Whether an organization pass or fail a pen test, it’s important to look at the results and find a way to improve their security architecture.
Review the Report
The first step is to review the tester’s after-action report, with a focus on answering a few key questions about the results and the test. Those questions include:
1. What areas of security resisted the pen tester?
A tester will typically evaluate or attempt multiple methods of compromise, and report on the effort expended on these secure areas. Like physical safes, which are rated by how long they can resist an expert safecracker, understanding the depth and breadth an organizations cybersecurity is the key to strengthening it.
2. What attack kill chain was utilized?
Review how the pen tester achieved their exploit against a business’ systems. How did they perform reconnaissance to discover vulnerabilities? What attack tools did they select and why? How did they access systems and execute the attack, while evading defenses and detection? Use the MITRE ATT&CK Framework to map out exactly how the compromise occurred.
At every stage, identify how defenses could have broken the kill chain and thwarted the attack. Be creative — the most effective defense isn’t always the most obvious. Detection and response capabilities are often a less-disruptive defense than additional levels of protection which may be cumbersome and impede usability.
Want to better understand pen tests? View our on-demand webinar, “Maximizing the Value of Penetration Tests.”
Take Action to Improve Security Posture Post-Pen Test
Once the above questions are answered and the test is thoroughly reviewed, it’s time to take action to harden the attack surface and strengthen the security posture.
Organizations should:
- Make strategic investments in their cybersecurity, prioritizing the improvements that will add the most robust defense against a range of attacks. Such improvements can span from tactical countermeasures — such as changes to configurations, permissions, rules, and procedures in existing systems — to strategic enhancements like new security investments, re-architecture activities, GPO changes, and more.
- Assign responsibility for change implementations, while understanding that primary responsibility will belong to IT department, but expect that cybersecurity is cross-function and a part of the changes may involve other functional groups across the organization.
- Implement the necessary changes, whether that requires executing existing plans or capabilities, like installing already-purchased security tools that have become shelfware or assigning clear escalation responsibilities for alerts; or executing improvements may require additional support from new or existing partners or vendors.
Explore how a Security Operations approach can harden an organization’s defenses before, during, and after a penetration test with the 2025 Arctic Wolf Security Operations Report.
Better understand what TTPs threat actors are utilizing and how they are executing attacks with the 2025 Arctic Wolf Threat Report.
