Advanced Penetration Testing Interview Questions

Security experts use all available tools to break a system during Penetration testing with the owner’s permission. This is a legal form of hacking, and it is a procedure wherein an attempt is made to breach a computer system’s security by accessing its internal network. This technique gives the business an idea of the potential software security breaches and the gaps that must be fixed. Qualified and reputable experts must only perform effective Penetration testing, ideally, those with academic qualifications in cybersecurity or hacking and certified Penetration testers. Understanding the significance of interview questions in the context of Penetration testing is crucial for both employers and candidates. These questions aim to delve into the depth of a candidate’s expertise, ensuring they possess the requisite skills and knowledge to conduct effective security assessments and fortify systems against potential threats.

Q1. What is the purpose of Penetration testing?

Penetration testing assists in identifying security flaws in the system before a hacker might exploit them or a user could discover them and report them. Finding flaws as quickly as possible during the software development lifespan is also simpler and more affordable.

Q2. What methodologies do you follow when conducting a Penetration test?

Penetration testing methodology follows industry-standard frameworks like the Open Source Security Testing Methodology Manual (OSSTMM), Penetration Testing Execution Standard (PTES), and National Institute of Standards and Technology Special Publication 800-115 (NIST SP 800-115). It begins with defining the scope and rules of engagement, followed by passive and active reconnaissance. Vulnerabilities are then identified and assessed using tools such as Nmap, Nessus, or Burp Suite. Exploitation is performed using Metasploit or custom scripts, with privilege escalation and lateral movement as needed. The final phase includes reporting all findings, risks, and remediation recommendations.

Q3. What are the different kinds of Penetration testing?

• Web Application Penetration Testing
• Wireless Penetration Testing
• Social Engineering Penetration Testing
• Network Penetration Testing
• Internal Penetration Testing
• External Penetration Testing

Q4. Can you explain how SQL Injection works and how you exploit it?

SQL Injection is a security attack that allows attackers to interfere with database queries by injecting malicious SQL statements into input fields. This can enable retrieval, modification, or deletion of data. Exploitation involves identifying input fields interacting with the database, such as login forms or search fields. Tools like SQLmap can automate the process of extracting data, dumping sensitive information, or escalating privileges. Manually crafted SQL payloads can also bypass authentication or access the database directly.

Q5. Describe Reconnaissance.

Reconnaissance is gathering more information about a particular target or area. In this sense, it is typically done at the beginning of a project to understand the surroundings, identify potential threats, evaluate the resources, and gather information.

Q6. Should Penetration Testing be performed regularly?

Penetration testing should be a standard procedure carried out before a product’s release, following minor or significant updates, after detecting unauthorized access through an intrusion detection system, or when generating a new version. To avoid potential threats, some organizations also perform Penetration tests regularly, such as three to four times a year.

Q7. Describe the Vulnerability Scanner.

Primetime computer system’s potential security flaws are discovered using vulnerability scanner software. This could scan a computer system to find known security flaws in the computer networks, system software, and applications and provide an overview of the system’s security.

Q8. How would you bypass a firewall or IDS during a Penetration test?

To bypass firewalls or Intrusion Detection Systems (IDS), it’s important to first understand how they work. Techniques like fragmentation or obfuscation can help avoid signature-based detection while encrypting or encoding payloads can evade IDS. Tunnelling methods, such as HTTP or DNS tunnels, can disguise malicious traffic as legitimate. Slow and low-volume attacks, like Slowloris, are also effective in evading detection by staying under bandwidth thresholds.

Q9. What are some typical ports to concentrate on when conducting a Penetration test?

• FTP (port 20 & 21)
• HTTP (port 80)
• HTTPS (port 443)
• NTP (port 123)
• SMTP (port 25)
• SSH (port 22)
• Telnet (port 23)

Q10. What are the important parts of the Pentesting Report?

A strong penetration testing report includes:

• Executive Summary: High-level overview for non-technical stakeholders.
• Scope and Objectives: Defines the systems tested and test goals.
• Methodology: Outlines frameworks used (e.g., OSSTMM, PTES) and tools.
• Findings and Vulnerabilities: Details vulnerabilities with severity ratings and CVE references.
• Exploitation and Impact: Describes successful exploits and potential risks.
• Recommendations: Provide prioritized remediation steps.
• Conclusion: Summarizes security posture and next steps.
• Appendices: Includes supporting technical data.

Q11. What does “File Enumeration” mean?

File enumeration is the process of providing more information about the folders inside the data file. It provides a thorough explanation, feature, position, and knowledge within a system to the organization and the ethical hacker.

Q12. Describe the Frame Injection Vulnerability.

A security flaw known as a frame injection vulnerability allows an attacker to insert any frames they choose into the traffic flowing through a website or application. This can be done by altering the components of an HTTP request header or by adding frames to the response the server sends to the browser.

Q13. How do you handle reporting after a Penetration test?

Reporting is a critical part of the Penetration testing process. Reports are structured with an executive summary for non-technical stakeholders and a detailed technical section for the security team. Each vulnerability found is described along with its potential impact and a step-by-step explanation of the exploitation process. Severity ratings based on CVSS scores and actionable remediation recommendations are included to guide fixing issues and mitigating future risks.

Q14. What are some techniques to escalate privileges after gaining initial access in a network?

After gaining initial access, techniques to escalate privileges include identifying vulnerabilities such as weak configurations or outdated software. On Windows systems, token impersonation can be used, while on Linux, searching for misconfigured sudo privileges or SUID binaries is effective. In Active Directory environments, techniques like Kerberoasting or Pass-the-Hash attacks can escalate privileges by abusing the Kerberos protocol.

Q15. What is a Buffer Overflow, and how would you exploit it?

A buffer overflow happens when a program tries to store more data in a buffer than it’s designed to handle, causing the extra data to spill over into nearby memory. To exploit it, vulnerable software or functions are identified using fuzzing techniques or tools like AFL (American Fuzzy Lop). A malicious payload is crafted to overwrite the return address, redirecting execution to shellcode for system control. In modern systems, bypassing defenses like DEP and ASLR is necessary, using techniques like Return-Oriented Programming (ROP).

Q16. What do you mean by SSRF?

Web applications can be vulnerable to Server-Side Request Forgery (SSRF), which enables an attacker to inject unauthorized requests into the application and grant unauthorized access to modify data. A user can be misled into sending a specifically designed query to the server, which an attacker can then use to take advantage of this vulnerability. Cross-site scripting (XSS) attacks frequently include SSRF attacks.

Q17. How would you approach testing an API for security vulnerabilities?

When testing an API, the approach begins with reviewing the API documentation to understand its functionality and endpoints. Common vulnerabilities are tested for, including authentication issues, lack of rate limiting, and injection attacks. Improper authorization, such as broken object-level authorization (BOLA), is also examined. Tools like Postman or Burp Suite assist in crafting requests and fuzzing parameters. Focus areas include identifying sensitive data exposure, improper error handling, and injection flaws like SQL injection (SQLi) or XML External Entity (XXE) attacks.

Q18. How does Port Scanning work?

Port scanning involves checking system ports for vulnerabilities, which hackers exploit to gain unauthorized access. Common tools for port scanning include Nmap, Netcat, and Zenmap, which send packets to ports and analyze responses. To protect against such attacks, organizations deploy firewalls and regularly update software to patch vulnerabilities.

Q19. What distinguishes Penetration testing from Vulnerability assessment?

Penetration Testing – Penetration testing elevates security assessment by simulating real-world attacks. It goes beyond identification by actively exploiting vulnerabilities to gauge how far an attacker could penetrate a system. It mirrors the methods hackers might use to test the strength of your security defenses. The aim is to see how well your system can hold up against actual threats.

Vulnerability Assessment – Vulnerability Assessment helps you find and prioritize potential security gaps in your system. It scans for known vulnerabilities but doesn’t attempt to exploit them, giving you a clear overview of risks. The aim is to assist you in addressing these vulnerabilities before attackers have the chance to exploit them.

Q20. What are SSL sessions and SSL connections, respectively?

A secure Socket Layer is a temporary peer-to-peer communications channel connecting each connection to a single SSL Session. An SSL session is a relationship between a client and a server typically established through the handshake protocol. Multiple SSL connections can share a defined set of parameters.

Penetration Testing with InfosecTrain

For a comprehensive understanding of Penetration testing, enroll in one of InfosecTrain’s in-depth training courses to gain extensive knowledge. These courses are designed to equip you with the skills and information required for conducting successful Penetration tests. To help you prepare for a lucrative Penetration testing career, we also offer specialized courses like the Pentester Combo Training & Certification Course. With hands-on experience and expert guidance, participants can effectively learn the latest techniques and tools used in the industry. Take the first step toward becoming a skilled Penetration tester and unlock numerous career opportunities in cybersecurity.

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