What Is Penetration Testing (Pentesting)?

Penetration testing, or pentesting, is a simulated attack on a computer system, network, or web application to identify security vulnerabilities. This process involves ethical hackers, acting with permission from the system owner, who mimics the strategies and actions of potential attackers, aiming to understand weaknesses and help remediate them. Pentesting ensures that any vulnerabilities are identified before malicious entities exploit them, thereby protecting sensitive data and maintaining system integrity.

Pentesting is a proactive approach to cybersecurity. It involves testing various aspects, including web applications, networks, or hardware. By identifying weaknesses, organizations can fix them before they are exploited maliciously. This testing provides valuable insights into an organization’s security posture, allowing for informed decisions to reinforce defenses and maintain security policies.

3 Reasons Companies Pentest

Companies conduct penetration testing (pentesting) for several key reasons, primarily to strengthen their cybersecurity defenses and comply with regulatory requirements.

1. Deeper Security Assessment

Penetration testing offers a deeper level of analysis than vulnerability assessments alone. While vulnerability assessments typically involve automated scans to identify known security flaws, pentesting goes further by simulating real-world attacks. Pentesters exploit vulnerabilities to demonstrate how actual attackers could breach systems, providing a clear understanding of the risks.

2. Minimizing False Positives and Finding Unknown Vulnerabilities

Pentesting combines automated tools with manual techniques to uncover both known and unknown vulnerabilities. By actively exploiting these weaknesses, pentesters reduce the likelihood of false positives, ensuring that any vulnerabilities identified are genuine risks. This process often reveals security gaps that may be overlooked by internal teams, especially since third-party pentesters bring an outsider’s perspective.

3. Supporting Regulatory Compliance

Penetration testing is not only a security best practice but also a requirement for compliance with various regulations and industry standards. For example, the Payment Card Industry Data Security Standard (PCI-DSS) mandates regular internal and external pentests for organizations handling credit card data. Other regulations, such as HIPAA and GDPR, also require strong security controls, and pentests can help verify that these controls are effective.

Who Carries Out Penetration Tests?

Penetration tests are performed by security experts known as ethical hackers or pentesters. These individuals possess a deep understanding of systems and networks and are skilled in identifying and exploiting potential vulnerabilities. They use the same tools and methodologies as malicious hackers but operate with authorization and a focus on improving security rather than causing harm.

Pentesters may work internally within an organization’s IT team, be hired by specialized cybersecurity firms, or work as freelancers. External testers bring a fresh perspective and can often simulate outsider attacks more effectively. Regardless of their affiliation, pentesters must maintain ethical standards, ensuring that all findings are reported responsibly and that testing does not disrupt business operations or compromise sensitive information.

Penetration Testing vs. Vulnerability Testing

Penetration testing and vulnerability testing aim to enhance security but differ in approach and scope.

Vulnerability testing scans systems to detect and list vulnerabilities without actually exploiting them. It helps identify potential security gaps and suggests remediation measures but does not assess how these vulnerabilities might be leveraged in a real-world attack.

Penetration testing goes a step further by actively exploiting vulnerabilities to determine the extent of damage an attacker could cause. This method provides a practical understanding of security risks and how they could impact an organization.

While vulnerability testing provides an overview of security issues, pentesting offers a more detailed analysis with proof of exploitability, making it a critical component of security assessments.

Learn more in our detailed guide to penetration testing vs vulnerability testing.

What Is PTaaS?

Penetration Testing as a Service (PTaaS) is a scalable, on-demand security testing solution that integrates continuous penetration testing into an organization's cybersecurity strategy. PTaaS platforms offer tools, dashboards, and reporting that streamline the pentesting process, providing more frequent and flexible testing than traditional methods.

PTaaS allows businesses to quickly initiate tests, receive real-time updates, and access detailed reports through a centralized online platform. This service model supports agile security testing, enabling organizations to quickly respond to emerging threats and compliance requirements. PTaaS provides a proactive approach to security, ensuring regular security validation without the logistical complexities of traditional pentesting.

What Is Tested in a Pentest?


Network Penetration Testing

Network penetration testing involves simulating attacks on an organization's network infrastructure to identify vulnerabilities. This includes testing firewalls, routers, VPNs, and other network devices. The goal is to discover weaknesses that could allow unauthorized access or manipulation of information.

Techniques used in network penetration testing may include evaluating open ports, identifying weak passwords, and testing for unpatched vulnerabilities. Network pentesting helps ensure that network configurations and policies are secure.

Web Application Penetration Testing

Web application penetration testing focuses specifically on web-based applications. This process identifies security weaknesses in applications that could be exploited by attackers to gain unauthorized access or retrieve sensitive data. It tests for common vulnerabilities such as SQL injection, cross-site scripting (XSS), and security misconfigurations.

Given the widespread use of web applications for business operations, securing them is critical. Pentesters use varied strategies to mimic real-world attacks and uncover vulnerabilities that developers might have overlooked.

Mobile Application Penetration Testing

Mobile application penetration testing aims to identify vulnerabilities within mobile apps across different platforms, such as iOS and Android. This type of testing evaluates areas like vulnerability to malware, data storage security, and unauthorized access risks.

Mobile app pentesting is crucial as mobile usage continues to expand, increasing the attack surface. Testers analyze the app's security both on the device and within connected network systems.

API Penetration Testing

API penetration testing focuses on identifying vulnerabilities within application programming interfaces (APIs). As APIs play a significant role in application communication and data exchange, securing them is vital. Testing reveals weaknesses that might allow unauthorized data access or system manipulation.

APIs are increasingly targeted due to their integral role in applications and services. Pentesters assess aspects such as authentication mechanisms, data validation, and user permissions.

Social Engineering Penetration Testing

Social engineering penetration testing evaluates an organization's susceptibility to manipulation tactics aimed at tricking employees into revealing confidential information or granting access. This testing simulates real-life scenarios, like phishing or pretexting, to determine how effectively employees can identify and respond to potential threats.

Social engineering remains a prevalent attack vector due to the human element being the weakest link in security. Pentesters conduct exercises that imitate common social engineering methods.

Cloud Penetration Testing

Cloud penetration testing examines the security posture of cloud-based environments, identifying vulnerabilities in configurations, storage, and data management processes. As more organizations migrate operations to the cloud, ensuring these platforms are secure is crucial.

Cloud environments present unique challenges due to their virtual nature and shared resources. Pentesters assess aspects like access controls, data privacy, and multi-tenancy security.

Physical Penetration Testing

Physical penetration testing evaluates the security measures of physical locations, such as offices or data centers, to identify vulnerabilities in access controls, surveillance systems, and other security protocols. This tests the organization's ability to detect and prevent unauthorized physical access. Pentesters use techniques like tailgating, badge cloning, or physical inspections to expose weaknesses in physical security.

What Are the Phases of Pentesting?


Reconnaissance

The reconnaissance phase in penetration testing involves gathering information about a target to identify potential entry points. This phase includes passive techniques like searching public records and active methods such as network scanning.

Reconnaissance is essential for effective pentesting as it provides insights into the system's defenses and potential weak spots. Data collected during this phase guides subsequent testing actions.

Target Discovery and Attack Planning

Target discovery and planning is the phase where pentesters identify specific assets to focus their efforts on, such as hosts, applications, or network components. This stage involves using tools and techniques to find live systems, open ports, and running services.

Attack planning involves refining the understanding of identified targets, examining their roles within the system, and considering potential vulnerabilities. Pentesters use this information to prioritize their actions, and identify the attack vectors most likely to succeed.

Exploitation

Exploitation is the phase where pentesters use the vulnerabilities discovered to gain unauthorized access or elevate their privileges within a system. This action-oriented phase tests whether vulnerabilities can be leveraged to perform illicit activities.

During exploitation, pentesters may employ various techniques like code injection or password cracking to demonstrate how vulnerabilities could be abused.

Escalation

Escalation involves pentesters attempting to gain higher access levels once initial access is achieved. It tests whether vulnerabilities can lead to privilege escalation, allowing broader system control or data access.

Successful escalation exercises highlight significant security gaps that could facilitate extensive damage if leveraged by malicious actors.

Cleanup and Reporting

Cleanup and reporting is the final phase of a penetration test, where traces of the testing activities are removed, and a comprehensive report is generated. Cleanup involves reverting any changes made during testing and ensuring that no residual effects remain.

The reporting component documents the findings, methodologies used, and the risks identified. This report provides actionable recommendations for mitigating identified vulnerabilities and improving security.

Key Penetration Testing Methods


External Testing

External testing focuses on assets visible on the internet, such as web applications, the company website, and email servers. It mimics attacks from outsiders attempting to breach the network perimeter, identifying vulnerabilities exposed to the external world.

During external testing, pentesters use various techniques like scanning, enumeration, and exploitation to assess defenses.

Internal Testing

Internal testing assesses security from within the network, simulating insider threats or potential breaches from compromised accounts. This method evaluates what could happen if an attacker bypasses perimeter defenses and gains internal access.

Challenges vary with internal testing due to different internal threat landscapes. Pentesters focus on aspects like privilege escalation, lateral movement, and data exfiltration.

Blind Testing

Blind testing involves providing pentesters with minimal information, mimicking a real attacker’s perspective. This method evaluates detection and response capabilities, testing an organization's ability to identify and react to unexpected threats.

This method challenges the security team’s readiness and system defenses, revealing gaps in the detection mechanisms. By discovering blind spots, organizations can implement better monitoring and alerting systems.

Double-Blind Testing

Double-blind testing keeps both the pentesters and the organization’s security team unaware of the forthcoming test. Only a few stakeholders know, increasing the realism of the exercise. This method tests the response procedures and how well security practices can identify and address a genuine threat.

Challenges can arise from the unpredictable nature of this testing method. It requires robust planning to avoid negative impacts on business operations.

Targeted Testing

Targeted testing, also known as the lights-on approach, involves both the pentesters and the organization’s IT team working together. Unlike blind testing, this method is collaborative, focusing on specific areas of concern with maximum input from internal resources.

This approach helps identify weaknesses with a strategic focus, often targeting critical assets. This collaboration enhances the test's accuracy and effectiveness while providing learning opportunities for internal teams.

Key Features of Penetration Testing Tools

Here are some of the key capabilities of modern pentesting tools.

Exploitation Frameworks

Exploitation frameworks are core components of penetration testing tools, providing a platform to automate and streamline the process of exploiting vulnerabilities. These frameworks include a library of pre-built exploits that target known vulnerabilities, allowing pentesters to simulate real-world attacks. By loading and configuring these exploits, testers can assess the impact of vulnerabilities on different systems. Exploitation frameworks also enable the customization of attacks, making it possible to craft tailored exploits that can bypass specific defenses. Additionally, they often integrate with other testing tools, allowing for smooth transitions from vulnerability discovery to exploitation, making the testing process more efficient and comprehensive.

Vulnerability Scanning

Vulnerability scanning is a critical feature that automatically detects and catalogs security weaknesses in systems, networks, and applications. These tools systematically search for unpatched software, misconfigurations, and outdated components that could expose systems to attacks. By scanning the environment and comparing its state against databases of known vulnerabilities, pentesters can generate a list of potential issues that require remediation. These scans are often the first step in a penetration test, as they provide a broad overview of the organization's security posture. Vulnerability scanning tools also often provide guidance on how to fix the discovered vulnerabilities, helping security teams prioritize and address the most critical risks.

Network Mapping and Discovery

Network mapping and discovery tools help penetration testers understand the structure and scope of an organization's network. These tools identify active devices, open ports, and running services across the network, creating a detailed blueprint that pentesters can analyze for weak points. By discovering network components that may be misconfigured or unnecessarily exposed, testers can identify potential attack vectors. This phase of testing is crucial for locating hidden or overlooked systems that could become targets during an attack. Detailed network maps also allow testers to understand how different systems interact, providing insights into the best paths for lateral movement within the network after an initial breach.

Password Cracking

Password cracking tools are designed to test the robustness of user authentication by attempting to break passwords using various techniques. These tools employ methods such as brute force attacks, where every possible password combination is tried, or dictionary attacks, which use lists of commonly used passwords. Cracking tools help pentesters identify weak passwords, default credentials, or poorly enforced password policies that could allow unauthorized access. This process highlights the risks associated with inadequate password management and can reveal gaps in an organization’s multi-factor authentication implementation. By exposing vulnerabilities in user credentials, password cracking tools help organizations strengthen their authentication systems and reduce the risk of account compromise.

Reporting and Documentation

The reporting and documentation features in penetration testing tools are essential for summarizing the findings of a test in a clear and actionable format. After vulnerabilities have been identified and exploited, these tools generate detailed reports that categorize issues based on their severity and potential impact. The reports typically include a description of each vulnerability, the method used to exploit it, and the risk it poses to the organization. Additionally, they provide recommendations for remediation, offering specific steps to fix or mitigate each issue. This documentation is critical for communicating the test results to various stakeholders, from IT teams who will implement the fixes to executives who need to understand the business risks. Comprehensive reporting ensures that all aspects of the penetration test are clearly recorded and helps organizations track improvements in their security posture over time.

Best Practices for Effective Penetration Testing


Obtain Proper Authorization

Before initiating a penetration test, it is critical to secure explicit authorization from the organization or entity being tested. This formal approval not only ensures that the pentesting activities are legal but also helps define the boundaries of the test. The agreement typically outlines the scope, which details the specific systems, networks, or applications that will be tested, along with the time frame, tools, and techniques that will be used. Without this authorization, penetration testing can be mistaken for malicious hacking, exposing pentesters and the organization to legal liabilities or compliance violations.

Additionally, well-defined authorization establishes a clear communication path, ensuring that the testing team and the organization remain aligned on expectations. It also prepares the organization for potential disruptions, such as system downtime or performance issues, that might occur during the test. Obtaining authorization safeguards both parties, preventing legal or operational consequences while allowing a controlled and effective security assessment.

Combine Automated Tools with Manual Testing

For comprehensive penetration testing, it’s crucial to combine automated tools with manual testing techniques. Automated tools are efficient at detecting common vulnerabilities across a wide range of systems and applications, scanning for known issues like unpatched software, default credentials, and misconfigurations. These tools are valuable for covering large areas of a network or system in a short amount of time, providing a solid foundation for initial testing.

However, automated tools are not foolproof; they are limited in their ability to understand complex business logic, contextual issues, or more advanced attack methods. This is where manual testing becomes indispensable. Manual testing allows skilled pentesters to dive deeper into system vulnerabilities, apply human intuition, and perform advanced attacks that automated tools might miss, such as logic flaws, multi-step exploits, and lateral movement. Combining both methods ensures a more thorough assessment—automated tools for breadth, and manual techniques for depth—thereby reducing the likelihood of critical vulnerabilities being overlooked.

Focus on Risk-Based Testing

Focusing on risk-based testing allows organizations to prioritize their security efforts by concentrating on vulnerabilities that present the highest risk to their most valuable assets. Not all vulnerabilities pose the same level of threat, and addressing them all indiscriminately can drain resources without necessarily improving the organization’s security posture. In risk-based testing, pentesters assess vulnerabilities not just by their technical severity, but by the potential damage they could cause if exploited.

For instance, a vulnerability in a publicly accessible web server that processes sensitive financial data would typically be ranked higher than one affecting an internal system with limited access. Pentesters work closely with the organization to identify critical systems and data, allowing them to focus on areas where a breach would have the most devastating impact. By aligning testing efforts with business priorities, risk-based testing helps organizations allocate time and resources more effectively, ensuring that the most dangerous vulnerabilities are addressed first, while lower-risk issues are dealt with later or mitigated through compensating controls.

Simulate Real-World Attack Scenarios

To achieve meaningful results from penetration testing, it’s essential to simulate real-world attack scenarios that closely resemble those used by actual cybercriminals. These scenarios go beyond simply identifying technical vulnerabilities; they test how an organization's security measures and defenses hold up under a targeted, deliberate attack. Pentesters replicate the techniques used by malicious hackers, such as spear-phishing campaigns, privilege escalation attempts, or lateral movement within a network.

This type of simulation provides a more accurate picture of how resilient an organization's security defenses are and how well the team can detect and respond to threats in real time. It’s not enough to know that vulnerabilities exist; organizations need to understand how these weaknesses could be exploited in practice and what the real-world impact would be. Simulating attack scenarios helps organizations identify gaps in their security controls, response procedures, and overall preparedness. It also offers valuable insights for improving incident response strategies, ensuring that teams are better equipped to handle genuine attacks.

Conduct Cross-Platform Pen Testing

As modern organizations operate across multiple platforms—including on-premises environments, cloud services, mobile applications, and web-based systems—conducting cross-platform penetration testing is essential to securing all aspects of their infrastructure. Each platform presents its own unique set of challenges and vulnerabilities, and testing only one segment of the environment can leave significant gaps in the organization's overall security posture. Cross-platform testing ensures that no area is overlooked, whether it's vulnerabilities in cloud configurations, weaknesses in mobile app security, or traditional network misconfigurations.

Furthermore, pentesters need to evaluate how different platforms interact with each other, as vulnerabilities in one system could potentially lead to compromise across multiple platforms. For example, an insecure API connecting a mobile app to a cloud backend could provide an attack path to critical data stored in the cloud. By testing across all platforms, pentesters can identify and help mitigate these interdependencies, ensuring that security is consistent and robust across the entire infrastructure. This comprehensive approach is particularly important for organizations with complex IT environments, where multiple systems and platforms interact daily.

Test for Business Logic Flaws

Testing for business logic flaws is an essential yet often overlooked component of penetration testing. Unlike technical vulnerabilities that arise from misconfigurations or coding errors, business logic flaws occur when the application’s design allows users to manipulate processes in unintended ways. These flaws are typically unique to the specific application or business process, and automated vulnerability scanners often fail to detect them. Business logic flaws can lead to severe security risks, including unauthorized transactions, data manipulation, or privilege escalation.

For example, an attacker might exploit a business logic flaw in an e-commerce application to manipulate pricing, bypass payment systems, or gain access to unauthorized discounts. Pentesters must manually review the application's workflows, understanding its intended functions, and then attempt to abuse those functions to achieve outcomes that the developers did not anticipate. By identifying and correcting business logic flaws, organizations can ensure that their critical operations remain secure, preventing malicious users from exploiting the very processes designed to support legitimate users.

Test Logging, Monitoring, and Alerting Mechanisms

An essential part of any security strategy is the ability to detect and respond to suspicious activities in real time. This makes testing the effectiveness of an organization’s logging, monitoring, and alerting mechanisms a crucial step in penetration testing. Pentesters simulate different types of attacks, such as data exfiltration or unauthorized access, to evaluate whether the organization’s systems are adequately logging these events. They also assess whether security teams receive timely alerts when abnormal or malicious activity occurs. It’s not enough for systems to simply log security events; they must be configured to generate useful, actionable alerts that prompt swift responses.

Pentesters often check whether the logged data is complete, whether critical events are being captured, and whether logs are securely stored to prevent tampering. Proper logging and monitoring are vital for detecting security breaches early, and strong alerting mechanisms ensure that security teams can take immediate action to mitigate any potential damage. By thoroughly testing these systems, organizations can improve their incident detection capabilities and reduce the time it takes to respond to security threats, thereby minimizing potential harm.