Kali Linux Interview Questions and Answers

This section covers frequently asked Kali Linux interview questions, focusing on its purpose, security concepts, and common tools used in penetration testing.

What is Kali Linux?

Kali Linux is a Debian-based Linux distribution designed for penetration testing. It comes pre-installed with a wide array of open-source security tools. It's an evolution of the BackTrack Linux distribution, developed by Offensive Security.

The Linux Kernel

The Linux kernel is the core of the Linux operating system. It manages the system's hardware and software resources, acting as an intermediary between the hardware and applications.

• Memory Management: Allocates and manages system memory.
• Process Management: Schedules and manages running processes.
• Device Drivers: Provides interfaces for hardware devices.
• System Calls and Security: Handles requests from processes and enforces security policies.

Components of Linux

The main components of the Linux operating system are:

• Hardware: Physical components (CPU, RAM, storage).
• Kernel: Core of the OS, managing resources.
• Shell: Command-line interface (or graphical shell) for interacting with the kernel.
• Utilities: System tools and applications.

Checking Memory Usage

Use the free command in the Linux terminal to view memory usage statistics.

The grep Command

The grep command searches for specific patterns within files or text streams. This is helpful for finding specific lines of text containing a word or phrase.

Penetration Testing

Penetration testing (pen-testing) is a security assessment where a security professional simulates real-world attacks to identify vulnerabilities in a system or network. This helps organisations understand their security posture and strengthen their defenses.

Goals of Penetration Testing

• Evaluate the effectiveness of security policies and controls.
• Assess the awareness and preparedness of employees regarding security.
• Identify and mitigate vulnerabilities before attackers can exploit them.

Vulnerability Testing vs. Penetration Testing

Vulnerability testing identifies potential weaknesses in a system. Penetration testing goes further, attempting to exploit those weaknesses to simulate a real attack.

Penetration Testing Methodologies

• Black-box testing: The tester has no prior knowledge of the system.
• White-box testing: The tester has full knowledge of the system's architecture and code.
• Gray-box testing: The tester has some limited knowledge of the system.

Cross-Site Scripting (XSS)

XSS is an attack where malicious scripts are injected into a website to steal user data or perform other harmful actions. It often targets vulnerabilities in web applications.

Sniffing and Spoofing

Sniffing: Intercepting network traffic to capture sensitive data (like passwords). Spoofing: Masquerading as another entity to gain unauthorized access or trust.

DDoS Attacks

A DDoS (Distributed Denial of Service) attack floods a target system with traffic from multiple sources, making it unavailable to legitimate users.

Diffie-Hellman Key Exchange

Diffie-Hellman is a cryptographic method for securely exchanging cryptographic keys over an insecure communication channel.

Cryptography

Cryptography is the science of securing communication and data, typically to prevent unauthorized access or modification.

Firewalls

A firewall is a network security system that monitors and controls incoming and outgoing network traffic based on pre-defined security rules. It helps protect networks and devices from unauthorized access.

Traceroute

Traceroute (or tracert on Windows) is a network diagnostic tool that traces the route a packet takes to reach a destination. It shows the intermediate routers or hops along the path.

HTTP Response Codes

HTTP response codes indicate the status of a request. They are grouped into five classes:

1. 1xx: Informational
2. 2xx: Success
3. 3xx: Redirection
4. 4xx: Client Error
5. 5xx: Server Error

Wireless Card Support in Kali Linux

Support for a wireless card in Kali Linux depends on the card's chipset and the availability of compatible drivers in the Linux kernel.

Troubleshooting Armitage Display Issues

If Armitage isn't displaying hosts:

• Ensure Metasploit Framework's workspace is set to default.
• Verify Armitage and Metasploit use the same database configuration.
• Check for multiple default workspaces in Metasploit.

Running Armitage on Kali Linux

Install Armitage using apt-get install armitage.

Fixing Database Errors in Kali Linux

1. Start the PostgreSQL database service: service postgresql start
2. If needed, recreate the Metasploit database: service metasploit restart

Using Armitage Against Internet Addresses

Always obtain permission before using Armitage (or any penetration testing tool) against a system you don't own.

Metasploit: Linux or Windows?

Linux is generally preferred for Metasploit due to broader feature support, especially for database integration and wireless exploits.

Pivoting

Pivoting in Metasploit redirects network traffic through a compromised system to access other systems that wouldn't be directly reachable.

Securing a Server

• Use secure protocols (SFTP, SSH, HTTPS).
• Implement strong passwords and access controls.
• Use firewalls and intrusion detection systems.
• Regularly update software.
• Use a VPN (Virtual Private Network).

Importance of DNS Monitoring

DNS monitoring helps track and analyze DNS traffic for security purposes. It provides insights into user activity, potential attacks, and can be useful for forensic analysis.

Encoding, Encryption, and Hashing

Strengthening User Authentication

• Enforce strong password policies (length, complexity, dictionary checks).
• Use multi-factor authentication (MFA).
• Limit login attempts.

Cloud vs. On-Premises Cybersecurity

Phases of a Network Intrusion Attack

1. Planning/Objective: Defining the attack's goal.
2. Reconnaissance: Gathering information about the target.
3. Execution: Carrying out the attack.
4. Exploitation: Exploiting vulnerabilities to gain access.
5. Maintenance: Maintaining access (if successful).
6. Covering tracks: Removing traces of the attack.

Kali Linux: Network Intrusion Attacks

This section delves into the stages of a typical network intrusion attack, providing context for penetration testing and security best practices.

Phases of a Network Intrusion Attack (Continued)

Continuing the discussion of network intrusion attacks, here are the remaining phases:

2. Reconnaissance: The attacker gathers information about the target network or system, searching for vulnerabilities. This might involve port scanning, analyzing network traffic, or searching online for information about the target.
3. Attack: The attacker attempts to exploit identified vulnerabilities to gain access to the system or network resources. A successful attack leads to a compromised system.

Understanding these phases helps security professionals design effective defense strategies and penetration testers conduct thorough security assessments.