Ultimate Linux Network Security for Enterprises: Master Effective and Advanced Cybersecurity Techniques to Safeguard Linux Networks and Manage Enterprise-Level Network Services

Cover Page....1 Title Page....2 Copyright Page....3 Dedication Page....4 About the Author....5 Technical Review Partner....6 About the Technical Reviewer....7 Acknowledgements....8 Preface....9 Errata....12 Table of Contents....16 1. Exploring Linux Network Security Fundamentals....22 Introduction....22 Structure....22 Introduction to Linux....22 Introduction to Computer Networks....27 IP Addressing....31 Subnetting....34 Transport Layer Protocols....36 Application Layer Protocols....38 Network Security....40 Firewall Configuration....42 Deception....44 Honeypot Methods....44 SSH Protocol....46 Access Control Lists....47 Virtual Private Network....48 Intrusion Prevention System (IPS) and Intrusion Detection System (IDS)....49 Web Security....50 Incident Response....51 Conclusion....52 2. Creating a Secure Lab Environment....53 Introduction....53 Structure....53 Virtualization....53 Installing VirtualBox....54 Installing Parrot Security VM on VirtualBox....58 Conclusion....63 3. Access Control Mechanism in Linux....64 Introduction....64 Structure....64 Access Control Mechanism in Linux....64 Types of Access Control....66 Discretionary Access Control....66 Mandatory Access Control....67 Role-based Access Control....68 Commands for Access Control....70 Standard Linux....73 Users....74 Centralized User Management....75 Permissions....78 Process Permissions....83 SELinux....85 SELinux Modes....86 Information Policies....88 Targeted Policy....88 Multi-Level Security Policy....89 Customizing SELinux Policies....91 Best Practices....91 Conclusion....92 4. Implementing Firewalls And Packet Filtering....93 Introduction....93 Structure....93 Firewall....93 Components of a Firewall....94 Working of a VPN....96 Intrusion Detection System (IDS)....97 Firewall Architecture....100 Packet Filtering....103 Types of Packet Filtering....104 Types of Firewalls....105 Circuit-Level Gateways....107 Application-Level Firewall....109 Stateful Multilayer Inspection....110 Use Cases....111 Uncomplicated Firewall....112 Testing Firewall Configurations....119 Conclusion....121 5. Mastering Cryptography for Network Security....123 Introduction....123 Structure....123 Understanding Cryptography....124 Types of Cryptography....124 Symmetric Encryption....124 Asymmetric Encryption....125 Encryption Algorithms....127 Hashing....131 Hashing Algorithms....132 Message Digest Algorithm 5 (MD5)....132 Secure Hash Algorithm (SHA)....133 RACE Integrity Primitives Evaluation Message Digest (RIPEMD-160)....134 Applications of Hashing....135 One Time Password (OTPs)....137 Cryptography Tools....138 Cryptanalysis....142 Brute-force Attack....142 Meet-in-the-Middle Attack....144 Rainbow Table Attack....145 DROWN Attack....146 Side-Channel Attack....148 Cryptanalysis Tools....149 Public Key Infrastructure....151 Steganography....152 Steganography Algorithms....153 Steganography Tools....154 Cryptography and Steganography....155 Conclusion....156 6. Intrusion Detection System and Intrusion Prevention System....157 Introduction....157 Structure....157 Understanding IDS....157 Types of IDS....159 Network-based Intrusion Detection System (NIDS)....159 Host-based Intrusion Detection System (HIDS)....160 Heuristics-based Intrusion Detection System....161 Methods to Detect Intrusions....163 Signature Recognition....163 Anomaly Detection....164 Types of Alerts....166 Setting Up IDS in Linux....166 Understanding IPS....172 Types of IPS....174 Setting Up IPS in Linux....176 Conclusion....178 7. Conducting Vulnerability Assessment with Linux....180 Introduction....180 Structure....180 Overview of Vulnerability Assessment....181 Importance of Linux in Cybersecurity....181 Prerequisites....181 Vulnerability Assessment....182 Penetration Testing....182 Setting Up the VAPT Lab....183 Initiating with Kali Linux....183 Deploying Kali Linux 2023.2....184 Installing Kali Linux in Virtual Box....184 Installing Essential Tools....187 Reconnaissance and Information Gathering....189 DNS reconnaissance....190 Understanding the Working of Scanning....200 Exploitation and Post-Exploitation....202 Overview of Report Writing....208 Components of Well-Crafted Reports....209 Case Studies and Real-World Examples....211 Case Study 1: WannaCry Ransomware Attack....211 Case Study 2: Stuxnet Worm....212 Learning from Successful Vulnerability Assessments....212 Implementing Lessons Learned....213 Conclusion....214 8. Creating Effective Disaster Recovery Strategies....215 Introduction....215 Structure....215 Importance of Disaster Recovery for Security Professional....215 Common Threats to Linux Systems....216 Disaster Recovery....217 Disaster Recovery Plan....218 DRP Case Studies....235 Scenario: A Data Center Destruction DisasterRecovery Case Study....237 Scenario: A DDoS Attack....239 Conclusion....240 9. Robust Security Incident Response Plan....241 Introduction....241 Structure....242 Rapid Detection....242 Preparation Phase....243 Key Elements to Focus....244 Detection Phase....246 Response Phase: Acting Swiftly and Strategically....257 Recovery Phase: Restoring Order and Strengthening Defenses....259 Documentation....261 Recovery....262 Case Study....264 10 Essential Linux Tools for Network and Security Pros....267 Conclusion....268 10. Best Practices for Linux Network Security Professionals....269 Introduction....269 Structure....269 Linux Security Tips and Best Practices....270 Firewall....272 Working of Firewalls in Linux....273 Intrusion Detection and Prevention System....277 Types of Intrusion Detection and Prevention Systems....278 Best Practices of Intrusion Detection and Prevention System....280 Snort and Suricata....281 Installing and Configuring Snort....283 Secure Shell (SSH)....284 Securing Your SSH Settings....285 Virtual Private Networks (VPNs)....287 OpenVPN and IPsec....288 Layer 2 Tunneling Protocol (L2TP)....289 Network Services Security....290 Securing Domain Name System (DNS) Servers....291 Securing Dynamic Host Configuration Protocol (DHCP) Services....292 Network Time Protocol (NTP) Security....292 Web Server Security....293 TLS/SSL Configuration for Encrypted Connections....294 Web Application Firewalls (WAFs)....296 Monitoring Network Traffic with Tools like Wireshark....296 File System Security....297 File Permissions and Ownership....298 File Permissions....298 Ownership....298 Security Tools and Utilities....298 Fail2ban for Intrusion Prevention....298 Security Scanners such as Nessus or OpenVAS....299 Conclusion....299 Index....301