What is Penetration Testing? A Comprehensive Guide to Pentesting

What is Penetration Testing?

Penetration Testing, often referred to as Pentest, is a security testing process used to identify vulnerabilities in computer systems. This process simulates the actions of attackers who exploit security weaknesses. By conducting a pentest, organizations can identify and address security vulnerabilities before a cyber attack occurs.

Importance of Penetration Testing

With the advancement of technology and the emergence of new systems, new security vulnerabilities are constantly being discovered. Organizations must be prepared to protect their computer systems from cyber threats. Regular pentesting is essential to ensure that security measures are up-to-date and effective.

Firms specializing in pentesting provide security testing services to organizations. These firms offer pentest proposals to organizations interested in their services. Under confidentiality agreements, certified cybersecurity experts conduct security tests on the organization’s systems. The experts performing these tests are known as Pentesters. They attempt to infiltrate the organization’s systems from the perspective of an attacker and prepare a pentest report detailing their findings.

Objectives of Penetration Testing

Identifying security vulnerabilities that affect an organization’s assets
Revealing risks and threats that impact the organization
Verifying the accuracy of implemented procedures, policies, and designs
Planning to secure systems to prevent security breaches by attackers
Determining the points that successful attackers can access
Modifying or improving the existing security architecture
Preventing potential image damage and financial loss due to security breaches
Evaluating the efficiency of security devices used by the organization
Identifying threats to prevent future attacks on organizations that have experienced security breaches

Approaches to Penetration Testing

Pentesting is conducted using three main approaches: Blackbox, Graybox, and Whitebox.

Blackbox Testing

In Blackbox testing, security experts are not provided with any information about the organization’s systems. The goal is to simulate the actions of attackers who have no prior knowledge of the system.

Graybox Testing

Graybox testing involves providing security experts with some information about the organization’s systems, such as IP addresses and server versions. This approach simulates the actions of attackers who have gained access to the organization’s network infrastructure.

Whitebox Testing

Whitebox testing provides security experts with complete information about the organization’s systems. This approach simulates the actions of malicious insiders who have full knowledge of the systems.

Penetration Testing Methodologies

Pentesting is conducted based on national and international methodologies to ensure standardization. Some of these methodologies include:

National Methodologies

TSE (TS-13638)
SOME Guide published by Civil Aviation
BDDK (Banking Regulation and Supervision Agency) General Communiqué on Penetration Tests for Information Systems

International Methodologies

NIST 800-115
OSSTMM
OWASP
ISSAF

Stages of Penetration Testing

Pentesting involves several stages:

Information Gathering

This stage involves collecting information about the target systems. It is the most crucial stage of pentesting. The more information an attacker has about an organization, the higher the likelihood of causing damage. Information gathering can be passive or active. Passive information gathering involves researching the target systems without direct interaction, while active information gathering involves interacting with the systems to collect data.

Enumeration

During enumeration, the goal is to gather as much information as possible about the target systems. This includes identifying open ports, services running on those ports, and their versions. This information is used to scan vulnerability databases and identify known vulnerabilities.

Vulnerability Scanning

This stage involves scanning for vulnerabilities that affect the target systems based on the gathered information.

Exploitation

In this stage, attempts are made to exploit the identified vulnerabilities to gain access to the target systems. Successful exploitation results in obtaining a session on the target system, allowing command and control.

Post-Exploitation

After gaining access to a system, the pentest continues to identify and exploit other devices connected to the organization’s network. This stage involves privilege escalation and lateral movement to gain control over other systems.

Reversing Changes

Before concluding a pentest, any changes made to the organization’s systems must be reversed to restore them to their original state.

Reporting

The final stage involves preparing a report detailing the findings of the pentest. This report includes an executive summary of the security audit, vulnerability identification cards with criticality levels and solution recommendations, and other relevant information.

Types of Penetration Testing

The process of pentesting varies depending on the type of target systems. Pentesting is conducted based on scenarios determined by the organization. Some types of pentesting include: