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CISSP Domain 3 Security Architecture and Engineering Detailed Notes Part I

PravinKarthik
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🎯 Purpose of Domain 3

This domain focuses on the foundational principles and practices needed to design, build, and maintain secure IT systems. It emphasizes how to integrate security throughout the system development life cycle (SDLC), evaluate architectures, and apply technical controls across various environments — from traditional IT to cloud and emerging technologies.

Considering the domain depth, i have summarized the notes in to two parts and this is the Part I. Happy Learning 1

📚 What You’ll Learn in This Domain -Part I

1. Secure Design Principles
Understand how to embed security early in system and software architecture using concepts like least privilege, defense in depth, fail-safe defaults, and zero trust.


2. Security Models and Architectures
Study formal security models such as Bell-LaPadula, Biba, Clark-Wilson, and how they apply to confidentiality, integrity, and access control.


3. Systems Security Requirements
Learn how to identify and select security controls based on the needs of the business and risk assessments.


4. Security Capabilities of Information Systems
Explore how components like memory protection, encryption, TPMs, and secure boot contribute to a secure computing environment.


5. Vulnerabilities in Architectures and Systems
Analyze the unique risks of servers, cloud systems, IoT, microservices, containers, and ICS, and how to mitigate them effectively.

🔐 3.1 Secure Design Principles

🎯 Objective

To ensure systems and processes are secure by design. This involves embedding security principles into engineering and architectural decisions, from early planning to post-deployment.

🔍 Key Secure Design Principles — Deep Dive

1️⃣ Threat Modeling

Definition: A structured process used to identify and evaluate potential threats and vulnerabilities during the design and development stages of a system.

Common Methodologies:

Implementation:

Example:
A financial app applies STRIDE to its login service and identifies spoofing (fake credentials) and tampering (modification of tokens). As a result, they implement MFA and JWT signature validation.

2️⃣ Least Privilege

Definition: Users, processes, or systems should be granted only the minimum access necessary to perform their function.

Benefits:

Examples:

Real-World Scenario:
An attacker compromises a developer’s account. Since the account lacks admin rights and access to production secrets, damage is limited.

3️⃣ Defense in Depth

Definition: Employing multiple, layered security controls throughout a system to reduce risk if one control fails.

Layers of Defense:

Example:
A healthcare system protects patient records using:

4️⃣ Secure Defaults

Definition: Systems should ship and deploy with security-focused default configurations.

Why Important:

Examples:

Real-World Scenario:
A company left a cloud database open to the public. If the default had been secure (private), the exposure would have been avoided.

5️⃣ Fail Securely

Definition: When a system experiences an error or failure, it should default to a secure state, not leave resources exposed.

Examples:

Real-World Scenario:
A bank ATM fails and displays a message. A “fail open” approach would allow access to the system — a major security risk. Instead, it locks and powers down.

6️⃣ Segregation of Duties (SoD)

Definition: No one person should have enough access or privileges to abuse the system on their own.

Types of SoD:

Example: In a finance system:

7️⃣ Keep it Simple and Small (Economy of Mechanism)

Definition: Simplify system design so it’s easier to understand, test, and secure.

Benefits:

Examples:

Real-World Scenario:
A startup rewrites its complex auth code using OAuth2 libraries. This reduces attack vectors and improves compliance.

8️⃣ Zero Trust / Trust But Verify

Zero Trust Concept:

Core Elements:

Real-World Application:
Google’s BeyondCorp architecture enables employees to work securely from anywhere, by authenticating every session and verifying device status.

9️⃣ Privacy by Design

Definition: Embedding privacy and data protection principles into systems and processes from the start, not as an afterthought.

Core Privacy Practices:

Example: A mobile health app collects only required medical information and encrypts all data both at rest and in transit. It also allows users to delete their data on demand.

Compliance Context:

🔟 Shared Responsibility Model (Cloud Security)

Definition: In cloud environments, security responsibilities are divided between the cloud provider and the customer.

Real-World Example:
In AWS, they secure the data center. You must:

Exam Insight: Know where responsibility lies in IaaS, PaaS, and SaaS models.

🔟Secure Access Service Edge (SASE)

Definition: A cloud-delivered architecture that converges networking and security functions into a single service.

Includes:

Use Case:

Example: A global company uses SASE to give employees secure access to internal tools, regardless of location, while applying centralized policies (e.g., block Dropbox uploads).

✅ Summary

🏛️ 3.2 Understand the Fundamental Concepts of Security Models

🔍 What Are Security Models?

Security models are abstract frameworks that define how access control and information flow are handled within a computing system. They are critical in designing systems that enforce confidentiality, integrity, and availability (CIA) through forma2l policies and access restrictions.

They act as the blueprint for enforcing:

These models help ensure secure system behavior and form the basis of many modern access control mechanisms (MAC, DAC, RBAC).

🔐 Security Models by Objective

📘 1. Bell-LaPadula Model (BLP) – Confidentiality First

🌟 Objective:

Prevent unauthorized disclosure of information.

🔑 Core Rules:

🛡️ Real-World Example:

A government worker with “Secret” clearance cannot read “Top Secret” files (no read up) and cannot write sensitive data into “Confidential” reports (no write down).

📌 Summary:

📗 2. Biba Model – Integrity First

🌟 Objective:

Ensure data remains uncorrupted by untrusted sources.

🔑 Core Rules:

🛡️ Real-World Example:

A junior employee cannot write data to the general ledger (no write up), and a senior accountant won’t read error-prone data from unverified sources (no read down).

📌 Summary:

📙 3. Clark-Wilson Model – Commercial Integrity & Transactions

🌟 Objective:

Ensure that data modifications are:

🔑 Core Components:

🛡️ Real-World Example:

In an enterprise resource system (ERP), a purchase order must be entered by one person, approved by another, and fulfilled by a third.

📌 Summary:

📕 4. Brewer-Nash Model – Dynamic Access Control / Conflict of Interest Model

🌟 Objective:

Prevent conflicts of interest by dynamically adjusting user access.

🔑 Concept:

🛡️ Real-World Example:

A cybersecurity consultant analyzing data for Company A will be automatically blocked from viewing Company B’s data in the same industry.

📌 Summary:

📓 5. Graham-Denning Model – Access Control Management

🌟 Objective:

Define secure rules for subject-object interactions (users, processes, and resources).

🔑 Features:

🛡️ Real-World Example:

A user creates a file, sets read-only access for a colleague, and later revokes it using OS-level access controls.

📌 Summary:

📔 6. Harrison-Ruzzo-Ullman (HRU) Model – Theoretical Access Verification

🌟 Objective:

Mathematically analyze if a system’s access control policy can maintain security over time.

🔑 Features:

🛡️ Real-World Example:

Used in academia or research to prove whether a security policy can become insecure through a chain of user actions.

📌 Summary:

📊 Summary

🛡️ 3.3: Select Controls Based Upon System Security Requirements

🎯 Objective:

Understand how to analyze security requirements for systems and apply appropriate security controls—technical, physical, and administrative—to mitigate risk, ensure compliance, and support CIA (Confidentiality, Integrity, Availability) goals.

🔍 What Are Security Controls?

Security controls are safeguards or countermeasures implemented to:

They are chosen based on system needs, risk profiles, data sensitivity, and business impact.

📂 Categories of Security Controls

🔁 Functional Types of Controls

🔄 Security Control Lifecycle

1️⃣ Identify Security Requirements

📘 Example: A healthcare SaaS must meet HIPAA requirements for confidentiality and auditability.

2️⃣ Conduct Risk Assessment

📘 Example: SCADA systems have high risk from cyber threats—availability becomes top priority.

3️⃣ Select Appropriate Controls

Match controls to:

Use control frameworks like:

📘 Example: Choose disk-level encryption to meet GDPR’s data protection mandate.

4️⃣ Implement Controls

Deploy controls based on roles, systems, and sensitivity

📘 Example: Enforcing RBAC in Azure AD for least privilege.

5️⃣ Monitor & Validate Effectiveness

🛠️ CIA Objective–Control Mapping

🛡️ 3.4: Understand Security Capabilities of Information Systems

🎯 Objective

To identify, analyze, and understand the built-in security features of modern information systems (IS) that ensure confidentiality, integrity, and availability (CIA) — by leveraging both hardware and software mechanisms such as memory protection, secure boot, TPM, encryption, and sandboxing.

🧠 Key Capabilities of Secure Information Systems

1️⃣ Memory Protection

✅ Purpose: Prevent one process from accessing or corrupting another process’s memory space.

🔧 Techniques:

💡 Real-World Use: Operating systems like Windows and Linux apply DEP + ASLR to stop malware from exploiting buffer overflows.

2️⃣ Trusted Platform Module (TPM)

✅ Purpose: Hardware chip used to ensure platform integrity, secure key storage, and enable hardware-rooted trust.

🔐 Functions:

💡 Example: BitLocker leverages TPM to encrypt disk contents and verify system integrity during boot.

3️⃣ Encryption & Decryption

✅ Purpose: Ensure data confidentiality and integrity, in storage and transit.

🔒 Encryption Types:

💡 Examples:

4️⃣ Hardware Security Module (HSM)

✅ Purpose: Dedicated physical device for secure cryptographic key generation, protection, and processing.

🔐 Capabilities:

💡 Example: Banks and payment processors use HSMs to protect keys used in card processing or SWIFT communications.

5️⃣ Secure Boot & Measured Boot

✅ Secure Boot: Ensures only signed and trusted firmware/OS components are loaded at startup.

✅ Measured Boot: Captures and records the hash of each component during boot for integrity validation via TPM.

💡 Example: On Windows, Secure Boot verifies UEFI and kernel drivers; Measured Boot ensures boot chain integrity.

6️⃣ Hardware Root of Trust

✅ Purpose: Establishes a trusted starting point at the hardware level, enabling verification of the bootloader and OS integrity.

💡 Examples:

Used in environments requiring strong tamper protection and chain-of-trust validation.

7️⃣ Trusted Execution Environment (TEE)

✅ Purpose: A secure enclave within the CPU where code and data are isolated and protected during execution.

🔐 Features:

💡 Examples:

Used by smartphones and cloud providers for secure workloads.

8️⃣ Sandboxing

✅ Purpose: Run untrusted or semi-trusted code in restricted, isolated environments to prevent access to system resources.

💻 Applications:

💡 Example: Each browser tab in Chrome runs in a sandbox to isolate crashes and limit exploit propagation.

9️⃣ Hypervisor Security (Virtualization Layer)

✅ Purpose: Enforces isolation between virtual machines (VMs) on the same hardware.

🔧 Types:

🔐 Security Features:

💡 Example: Cloud providers use hypervisors to isolate tenants in IaaS platforms.

🔟 Access Control Enforcement Mechanisms

✅ Purpose: Define and enforce who can access what resources, and how.

🔒 Models:

💡 Example: Linux systems use SELinux (MAC) to control daemon privileges beyond standard Unix permissions.

📊 Summary

3.5: Assess and Mitigate the Vulnerabilities of Security Architectures, Designs, and Solution Elements

🎯 Objective

To identify and mitigate vulnerabilities across a diverse set of system architectures and solution elements by applying secure design principles and security controls appropriate to each system type.

These systems include:

🔍 Detailed Vulnerability Assessment & Mitigation by Architecture

1️⃣ Client-Based Systems

Common Risks:

Mitigation Strategies:

Real-World Example:
Corporate laptops configured with BitLocker, restricted USB access, and monitored using CrowdStrike Falcon.

2️⃣ Server-Based Systems

Common Risks:

Mitigation Strategies:

Real-World Example:
Hardened Linux web servers configured with Fail2Ban, SELinux, and 2FA-enabled SSH.

3️⃣ Database Systems

Common Risks:

Mitigation Strategies:

Real-World Example:
Secure PostgreSQL setup with pgAudit, TLS encryption, and access limited via roles.

4️⃣ Cryptographic Systems

Common Risks:

Mitigation Strategies:

Real-World Example:
TLS 1.3 enforced on web servers with HSTS, AES-GCM encryption, and Let’s Encrypt automation.

5️⃣ Industrial Control Systems (ICS)

Common Risks:

Mitigation Strategies:

Real-World Example:
An energy utility segments its OT and IT networks and monitors ICS traffic using Nozomi Guardian.

6️⃣ Cloud-Based Systems (SaaS, IaaS, PaaS)

🟠 SaaS Risks:

Mitigations:

🔵 IaaS Risks:

Mitigations:

🟣 PaaS Risks:

Mitigations:

Real-World Example:
AWS Lambda with strict IAM, encrypted environment variables, and integrated GuardDuty alerting.

7️⃣ Distributed Systems

Common Risks:

Mitigation Strategies:

Real-World Example:
A Kubernetes-based distributed app using SPIFFE identities and mTLS between pods.

8️⃣ Internet of Things (IoT)

Common Risks:

Mitigation Strategies:

Real-World Example:
Smart home hubs using certificate-based authentication and encrypted MQTT communication.

9️⃣ Microservices / APIs

Common Risks:

Mitigation Strategies:

Real-World Example:
REST APIs behind AWS API Gateway, integrated with Cognito for auth and CloudWatch for logs.

🔟 Containerization

Common Risks:

Mitigation Strategies:

Real-World Example:
Containers scanned with Trivy, run as non-root, and isolated using PodSecurityPolicies.

1️⃣1️⃣ Serverless

Common Risks:

Mitigation Strategies:

Real-World Example:
GCP Cloud Functions limited by least privilege and validated by Cloud Endpoints.

1️⃣2️⃣ Embedded Systems

Common Risks:

Mitigation Strategies:

Real-World Example:
Medical device using ARM TrustZone and signed firmware for integrity.

1️⃣3️⃣ High-Performance Computing (HPC) Systems

Common Risks:

Mitigation Strategies:

Real-World Example:
University HPC clusters using Slurm scheduler with user quotas and encryption of scratch space.

1️⃣4️⃣ Edge Computing Systems

Common Risks:

Mitigation Strategies:

Real-World Example:
Retail kiosks using Intel TPM, auto-patching, and encrypted disk for offline operation.

 1️⃣5️⃣ Virtualized Systems

Common Risks:

Mitigation Strategies:

Real-World Example:
Enterprise uses VMware NSX to inspect VM traffic and isolate PCI-compliant systems.

📌 Summary

📘 Final CISSP Study Tips

3.1

3.2

3.3

3.4

3.5

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