Knowledge Base

What is Pentest (Penetration Testing)?

Pentest is an authorized simulated attack performed on a computer system, network, or web application to identify and exploit security vulnerabilities. The goal is to bypass security measures and reveal potential damages, just as a real attacker might do. Pentest results help organizations address vulnerabilities and improve their security posture.

Important Note: Pentest should always be an authorized and planned activity. Unauthorized penetration attempts are illegal and can have serious legal consequences.

Why Should Pentests Be Performed?

There are many reasons to perform pentests. The most important ones are:

• Identifying Security Vulnerabilities: Pentests reveal weaknesses in firewalls, IDS/IPS systems, and other security measures.
• Assessing Risks: Pentests help assess the potential damages that may arise if security vulnerabilities are exploited.
• Meeting Compliance Requirements: Many regulations (such as PCI DSS, HIPAA) require organizations to conduct regular pentests.
• Increasing Security Awareness: Pentest results can be used to increase employee security awareness.
• Optimizing Security Investments: Pentest results help ensure that security investments are made in the right areas.

Real-Life Example: An e-commerce company suffered a SQL injection attack because it did not regularly conduct pentests. Attackers accessed the customer database and stole credit card information. This incident damaged the company's reputation and caused significant financial losses.

What are the Types of Pentests?

Pentests can be divided into different types depending on the targeted systems and the scope of the test:

• Black Box Pentest: The test expert has no information about the target system. They act like a real attacker and analyze the systems from the outside.
• White Box Pentest: The test expert has detailed information about the target system (source code, network diagrams, etc.). This type of pentest allows for in-depth analysis of the internal workings of the systems.
• Gray Box Pentest: The test expert has limited information about the target system. This combines the advantages of both black box and white box pentests.

In addition, pentests can also be classified according to the target systems:

• Web Application Penetration Testing: Targets security vulnerabilities in web applications (SQL injection, XSS, CSRF, etc.).
• Network Penetration Testing: Targets security vulnerabilities in the network infrastructure (misconfigured devices, weak passwords, etc.).
• Mobile Application Penetration Testing: Targets security vulnerabilities in mobile applications (data storage issues, authorization errors, etc.).
• Wireless Network Penetration Testing: Targets security vulnerabilities in wireless networks (weak encryption, unauthorized access points, etc.).
• Social Engineering Penetration Testing: Aims to obtain information or access systems by exploiting human weaknesses (phishing, pretexting, etc.).

What are the Pentest Stages?

A pentest typically consists of the following stages:

1. Planning and Scoping: The purpose, scope, timeline, and rules of the pentest are determined. It is decided which systems will be tested and which testing methods will be used.
2. Information Gathering (Reconnaissance): As much information as possible is gathered about the target system. This includes open-source intelligence (OSINT), network scanning, and port scanning techniques.
3. Vulnerability Analysis: Security vulnerabilities in the target systems are identified using the collected information. Automated vulnerability scanners and manual testing methods are used.
4. Exploitation: Attempts are made to gain access to the systems by exploiting the identified security vulnerabilities. This may involve using exploits that take advantage of vulnerabilities or developing custom exploits.
5. Maintaining Access: After gaining access to the systems, methods are developed to maintain access. This may involve installing backdoors or escalating privileges.
6. Reporting: The results of the pentest are presented in a detailed report. The report includes the security vulnerabilities found, risk assessment, proof of exploitation, and improvement recommendations.

Step-by-Step Instructions: To find an SQL injection vulnerability in a web application, you can follow these steps:

1. Examine the input forms or URL parameters of the web application.
2. Submit inputs containing special characters (', ", --, ;) to attempt SQL injection.
3. Examine the errors returned by the application. If the errors contain information about SQL queries, there may be an SQL injection vulnerability.
4. Try to list all records by entering something like ' OR '1'='1.
5. Try to delete the database by entering something like '; DROP TABLE users; --.
6. If these attempts are successful, an SQL injection vulnerability exists.

Code Example (SQL Injection):

<?php
$username = $_POST['username'];
$password = $_POST['password'];

$query = "SELECT * FROM users WHERE username = '$username' AND password = '$password'";

$result = mysqli_query($connection, $query);

if (mysqli_num_rows($result) > 0) {
  // Login successful
} else {
  // Login failed
}
?>

This code is vulnerable to SQL injection. Because the input received from the user is directly added to the SQL query. An attacker can access the information of all users by entering a value such as ' OR '1'='1 in the username field.

Which Tools Are Used?

Many different tools can be used during pentesting. Some of the most popular tools are:

• Nmap: Used for network scanning and port scanning.
• Burp Suite: Used for web application pentesting. It acts as a proxy, allowing you to analyze and manipulate HTTP traffic.
• Metasploit: Used for vulnerability exploitation and exploit development.
• Wireshark: Used for network traffic analysis.
• Nessus: Used for vulnerability scanning.
• OWASP ZAP: A free and open-source web application security scanner.

Tool Comparison Table:

How to Evaluate Pentest Results?

Pentest results should be evaluated according to the severity and potential impact of the security vulnerabilities found. Security vulnerabilities are generally classified as follows:

• Critical: Security vulnerabilities that can lead to complete takeover of systems or significant data loss.
• High: Security vulnerabilities that can lead to partial takeover of systems or access to sensitive data.
• Medium: Security vulnerabilities that can affect the operation of systems or cause information leakage.
• Low: Security vulnerabilities that do not directly affect the security of systems but can potentially be exploited.

Vulnerabilities identified in the pentest report should be addressed in order of priority. Critical and high-risk vulnerabilities should be addressed as soon as possible. Medium and low-risk vulnerabilities can be addressed in the longer term.

Important Note: Pentest results are only a starting point. Organizations should conduct regular pentests to address vulnerabilities and continuously improve their security posture.

Case Study: A bank found a critical vulnerability in its annual pentests. This vulnerability allowed attackers to access the bank's internal network and steal sensitive customer data. The bank immediately addressed this vulnerability and strengthened its security measures. This prevented a potential data breach.

What is the Cost of a Pentest?

The cost of a pentest can vary depending on many factors. These factors include:

• Scope of the Pentest: The number and complexity of the systems to be tested affect the cost.
• Type of Pentest: Black box pentests are generally cheaper than white box pentests.
• Experience of the Test Expert: More experienced test experts generally charge higher fees.
• Test Duration: The duration of the pentest affects the cost.
• Reporting Detail: More detailed reports are generally more expensive.

Pentest Cost Table (Estimated):

Important Note: The cost of a pentest should be considered an investment. Addressing security vulnerabilities avoids larger costs in the long run by preventing potential data breaches and reputational damage.

What Should a Pentest Report Look Like?

A pentest report should describe in detail the purpose, scope, methodology, findings, and recommendations of the pentest. A good pentest report should include the following elements:

• Summary: A brief summary of the pentest and highlighting the most important findings.
• Scope: A detailed description of the systems tested and the scope of the test.
• Methodology: A description of the testing methods and tools used.
• Findings: A detailed description of the security vulnerabilities found, risk assessment, and proof of exploitation.
• Recommendations: Practical and actionable recommendations for remediating the security vulnerabilities.
• Appendices: Inclusion of data obtained during testing, screenshots, and other supporting materials.

Visual Explanation (Diagram): A pentest report may include a diagram showing the impact of the security vulnerabilities found on the system. This diagram helps to visually demonstrate how vulnerabilities can be exploited and which systems may be affected.

Important Note: In addition to being a technical document, the pentest report should be written in a language that management can understand. The report should clearly state the impact of the security vulnerabilities on the business and what needs to be done to remediate them.

What Needs to Be Done After a Pentest?

After the pentest is completed, the following steps should be taken:

1. Remediate Security Vulnerabilities: The security vulnerabilities identified in the pentest report should be remediated in order of priority.
2. Strengthen Security Measures: In addition to remediating security vulnerabilities, general security measures should also be strengthened (firewall rules, IDS/IPS configurations, access controls, etc.).
3. Train Employees: Training should be organized to increase employees' security awareness.
4. Retest: Retesting should be performed to verify that the security vulnerabilities have been remediated.
5. Continuous Monitoring: Systems should be continuously monitored and prepared for potential security incidents.

Important Note: Pentesting should not be a one-time activity. Organizations should conduct regular pentests to continuously improve their security posture.