Network Security: Designing a Secure Network

Define a Process for Designing Network Security

• A network is a collection of interconnected devices and systems that communicate to share resources and information.
• Network design involves planning and structuring a network's layout and components to ensure efficient and secure communication.

Network Security

• Network security involves protecting the integrity, confidentiality, and availability of data and resources as they are transferred across or stored within a network.
• Key components of network security:
  • Access Control
  • Encryption
  • Firewalls
  • Intrusion Detection and Prevention Systems (IDS/IPS)
  • Security Policies
  • Incident Response

Network Management

• Network management involves monitoring, maintaining, and optimizing a network to ensure efficient and reliable operation.
• Key components of network management:
  • Monitoring
  • Configuration Management
  • Performance Management
  • Fault Management
  • Security Management
  • Reporting and Documentation

Designing Network Security

• Designing network security involves a structured process to ensure comprehensive protection against threats and vulnerabilities.
• The process can be broken down into three main phases: Planning, Building, and Managing.

Planning Phase

• Identify business needs and regulatory requirements.
• Conduct risk assessment, including asset identification, threat analysis, vulnerability assessment, and risk evaluation.
• Develop security policies, including access control and incident response plans.
• Design security architecture, including network segmentation, firewalls, IDS/IPS, and encryption.

Building Phase

• Implement infrastructure, including network segmentation, firewalls, and Virtual Private Networks (VPNs).
• Deploy security tools, including IDS/IPS, anti-malware, and encryption.
• Implement access control mechanisms, including authentication, authorization, and audit logs.
• Harden systems through patch management and configuration management.
• Conduct testing and validation, including penetration testing, security audits, and user training.

Managing Phase

• Monitor and surveil the network for suspicious activities.
• Implement continuous monitoring, Security Information and Event Management (SIEM) systems, and alerts and notifications.
• Manage incidents, including detection, response, and recovery.
• Maintain and update security measures, including regular updates, configuration reviews, and compliance audits.
• Continuously improve security through policy review, feedback loops, training, and security metrics.

Network Security Threats

• Malware: malicious software designed to harm or exploit systems; types: viruses, worms, trojan horses, ransomware, spyware; impact: unauthorized access, data theft, system disruption
• Phishing: social engineering attack where attackers impersonate trustworthy entities to trick individuals into revealing sensitive information; forms: email phishing, spear phishing, vishing (voice phishing), smishing (SMS phishing); impact: unauthorized access, identity theft, financial loss
• Denial-of-Service (DoS) and Distributed Denial-of-Service (DDoS) Attacks: overloading a system, network, or service with excessive traffic to disrupt normal functioning; impact: service outage, network slowdown, loss of availability
• Man-in-the-Middle (MitM) Attacks: intercepting and potentially altering communication between two parties without their knowledge; forms: eavesdropping, session hijacking, SSL stripping; impact: data interception, unauthorized access
• SQL Injection: exploiting vulnerabilities in web applications by injecting malicious SQL code into input fields; impact: unauthorized access to databases, data manipulation
• Cross-Site Scripting (XSS): injecting malicious scripts into webpages viewed by other users; forms: stored XSS, reflected XSS, DOM-based XSS; impact: cookie theft, session hijacking, defacement
• Zero-Day Exploits: targeting undiscovered vulnerabilities (zero-day vulnerabilities) before a patch or fix is available; impact: unauthorized access, data breaches, system compromise
• Brute Force Attacks: repeatedly attempting various combinations of usernames and passwords until the correct credentials are found; impact: unauthorized access, account compromise
• Eavesdropping (Packet Sniffing): unauthorized interception and monitoring of network traffic; impact: unauthorized access to sensitive information
• DNS Spoofing: redirecting DNS queries to malicious sites; impact: man-in-the-middle attacks, phishing, data theft
• Social Engineering: manipulating individuals into divulging confidential information or performing actions against their interests; forms: impersonation, pretexting, baiting; impact: unauthorized access, data breaches, compromised security
• Insider Threats: malicious actions or negligence by individuals within an organization; forms: intentional data theft, accidental data exposure; impact: data breaches, compromised security

Network Vulnerabilities

• Weak Passwords: passwords that are easy to guess or are not strong enough can be exploited by attackers; mitigation: enforcing strong password policies and using multi-factor authentication (MFA) where possible
• Outdated Software and Patching: failure to update and patch operating systems, applications, and network devices leaves vulnerabilities open for exploitation; mitigation: regularly applying security patches
• Unsecured Network Protocols: insecure or outdated network protocols expose sensitive information to eavesdropping; mitigation: using secure protocols (e.g., HTTPS instead of HTTP) and disabling deprecated protocols
• Lack of Encryption: failure to encrypt sensitive data during transmission or storage exposes it to unauthorized access; mitigation: implementing encryption protocols, such as SSL/TLS for data in transit and encryption for stored data
• Unsecured Wireless Networks: open or poorly configured Wi-Fi networks can be exploited by unauthorized users; mitigation: using strong encryption (WPA3), complex passwords, and regularly updating Wi-Fi passwords
• Insufficient Access Controls: inadequate access controls lead to unauthorized access or privilege escalation; mitigation: implementing the principle of least privilege, regularly reviewing user access levels, and ensuring proper user authentication
• Misconfigured Firewalls and Routers: improperly configured firewalls and routers allow unauthorized access to the network; mitigation: regularly reviewing and updating firewall rules to ensure alignment with security policies
• Phishing Attacks: social engineering attacks exploit human vulnerabilities to gain unauthorized access; mitigation: employee training and awareness programs
• Malware and Viruses: malicious software can exploit vulnerabilities to infiltrate a network; mitigation: employing anti-malware tools, keeping them updated, and regularly scanning for malware
• Unrestricted Physical Access: physical access to network infrastructure can lead to unauthorized manipulation; mitigation: restricting physical access to network devices and securing server rooms

Threat Model

• Asset Identification: identifying and enumerating all assets within the network, including hardware, software, data, and human resources
• Threat Enumeration: enumerating potential threats and vulnerabilities that could impact the network, including external and internal threats, such as malicious actors, malware, insider threats, and natural disasters
• Vulnerability Assessment: conducting a thorough vulnerability assessment to identify weaknesses in the network
• Risk Assessment: evaluating the likelihood and potential impact of identified threats and assigning risk levels based on the combination of threat likelihood and impact
• Attack Surface Analysis: analyzing the network's attack surface, including all points where an attacker could potentially gain unauthorized access
• Security Controls Evaluation: evaluating the effectiveness of existing security controls, such as firewalls, intrusion detection systems, access controls, and encryption mechanisms
• Incident Response Planning: developing an incident response plan outlining the steps to be taken in the event of a security incident