CISSP Software Development Security: Understanding the Software Development Lifecycle (SDLC)

Introduction

Software development security is a critical component of the CISSP certification, covering Domain 8 of the eight core areas. This domain accounts for 10% of the CISSP exam and focuses on securing software throughout its lifecycle.
Other areas are

1.  Security and Risk Management
2.  Asset Security
3.  Security Architecture and Engineering
4.  Communication and Network Security
5.  Identity and Access Management (IAM)
6.  Security Assessment and Testing
7.  Security Operations
8.  Software Development Security

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1. Software Development Lifecycle (SDLC) Overview

• Importance of integrating security at every stage

• Key SDLC methodologies

The Software Development Lifecycle (SDLC) is a structured approach to software creation, ensuring security is integrated at every stage. From initial planning to deployment and maintenance, SDLC methodologies help organisations mitigate risks, enforce security controls and maintain compliance.

2. Software Platforms and Development Models

Software can be developed for various platforms, including:

• Client-server models – Applications that rely on backend infrastructure.

• Standalone applications – Software that operates independently, such as a calculator app with no backend dependencies.

3. Development Methodologies and Security Considerations

• Waterfall Model (Challenges in late-stage security)

• Spiral Model (Iterative security improvements)

• Agile Development (Security integration in rapid development)

Different methodologies guide software development, each with unique security implications:

Waterfall Model

• Introduced in the 1970s, this rigid, linear approach moves through phases sequentially.

• Security is often addressed late in the process, making it harder to implement changes.

Spiral Model

• Consists of four iterative phases, integrating risk assessment at each stage.

• Allows for continuous security improvements throughout development.

Agile Development

Agile methodologies prioritize rapid development and adaptability. The four Agile value statements emphasize:

1. Individuals and interactions over processes and tools.

2. Working software over comprehensive documentation.

3. Customer collaboration over contract negotiation.

4. Responding to change over following a rigid plan.

Agile fosters face-to-face collaboration between business and development teams, ensuring security is integrated early.

4. Maturity Models for Software Security

• CMMI, IDEAL, SAMM (Security benchmarks)

Standard benchmarks help organisations assess their software security maturity:

• CMMI (Capability Maturity Model Integration) – Five levels: Initial, Managed, Defined, Quantitatively Managed, Optimizing.

• IDEAL Model – A structured improvement framework.

• SAMM (Software Assurance Maturity Model) – Security-focused guidance from OWASP.

5. Change Management & Secure Configuration

Software development is never truly finished—continuous updates and security patches are essential. Change management ensures orderly updates without disrupting operations:

• Request Control – Evaluates new feature requests.

• Change Control – Formal documentation of changes (RFCs).

• Release Control – Quality assurance testing before deployment.

Software Configuration Management (SCM)

SCM ensures version control and traceability across environments:

• Development Environment – Where code is written and tested.

• Test Environment – Validates functionality and security.

• Staging Environment – Pre-production testing.

• Production Environment – Live deployment.

6. Automation and DevSecOps in Secure Development

Modern development integrates automation and DevOps to enhance security:

• Continuous Integration/Continuous Deployment (CI/CD) – Automates testing and deployment.

• Immutable Infrastructure – Uses scripted baselines to ensure consistency.

• DevSecOps – Embeds security into DevOps workflows.

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1. Introduction to Software Quality Assurance (SQA)

• Importance of SQA in secure software development

• Key objectives: reliability, security, and compliance

Software Quality Assurance (SQA) is a critical component of secure software development, ensuring that applications meet functional, security and compliance requirements. It involves code reviews, testing methodologies and risk assessments to identify vulnerabilities before deployment.

2. Code Review: The First Line of Defence

• Manual vs. automated code reviews

• Peer-to-peer reviews and structured inspections (e.g., Fagan Inspection)

Manual code reviews are essential for detecting security flaws early. They can be formal or informal, with peer-to-peer reviews being a common practice.

Fagan Inspection: A Structured Approach

The Fagan Inspection is a six-step formal review process:

1. Planning – Define objectives and scope.

2. Overview – Introduce the code to reviewers.

3. Preparation – Reviewers analyse the code independently.

4. Meeting – Discuss findings and identify defects.

5. Rework – Developers fix identified issues.

6. Follow-up – Verify corrections and finalize the review.

Alternatively, cycle reviews provide a continuous feedback loop, ensuring security improvements throughout development.

3. Software Testing: Validating Security and Performance

Frequent testing ensures software functions correctly under real-world conditions. Common testing methods include:

• Validation and Verification, stress testing, and regression testing– Confirms software meets requirements.

• Stress and Load Testing – Simulates high-traffic scenarios to test system resilience.

• User Acceptance Testing (UAT) and its role in security assurance – Ensures usability and functionality.

• Regression Testing – Identifies unintended side effects from code changes.

4. Code Security Testing: Identifying Vulnerabilities

Security testing is crucial for detecting weaknesses before attackers exploit them.

• Static Analysis – Examines source code for vulnerabilities without execution.

• Dynamic Analysis – Tests running applications for security flaws.

• Synthetic Transactions – Simulates user interactions to detect security gaps.

• Fuzz Testing – Injects random or malformed inputs to uncover weaknesses.

5. Secure Code Repositories & Version Control

• Best practices for managing code securely

• Preventing exposure of sensitive data in repositories

Version control systems like Git ensure secure code management:

• Tracking changes and rolling back versions when needed.

• Logging modifications for auditing and compliance.

• Ensuring code integrity using hash functions to verify authenticity.

Developers must keep secrets out of repositories, using secure storage solutions to prevent exposure.

6. Automated Security Testing Tools

OWASP ZAP is a powerful tool for testing web application security. It analyses input validation, payload handling and request-response behaviour, helping developers identify and fix security flaws before deployment. Integrating security testing into CI/CD pipelines.

7. Continuous Improvement in Software Quality

• Implementing feedback loops for ongoing security enhancements

• Metrics and benchmarks for measuring software quality

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Application Attacks: Understanding Threats and Mitigation Strategies

1. Introduction to Application Security Threats

Application security is a critical aspect of software development, as vulnerabilities can be exploited by attackers to gain unauthorized access, manipulate data, or disrupt services. Understanding common application attacks and their mitigation strategies is essential for securing software throughout its lifecycle.

2. Common Application Attack Types and Mitigation Strategies

2.1 Injection Attacks

Injection attacks occur when an attacker manipulates input fields to execute unintended commands. The most common types include:

• SQL Injection – Exploiting database queries to retrieve or modify sensitive data.

• Command Injection – Executing system commands through vulnerable applications.

• LDAP Injection – Manipulating directory queries to gain unauthorized access.

• Mitigation: Use parameterized queries, prepared statements to prevent SQL injection and strict input validation with sanitization to block malicious payloads.

2.2 Cross-Site Scripting (XSS)

XSS attacks occur when an attacker injects malicious scripts into web applications, which are then executed by unsuspecting users.

Types of XSS:

• Stored XSS – Malicious scripts are permanently stored in the application.

• Reflected XSS – Scripts are executed when a user clicks a manipulated link.

• DOM-Based XSS – Exploits JavaScript execution within the browser.

• Mitigation: Implement Content Security Policy (CSP) to restrict script execution, encode user input to prevent malicious script injection and sanitize output.

2.3 Cross-Site Request Forgery (CSRF)

• How attackers trick users into performing unintended actions on authenticated web applications.

• Mitigation: Use anti-CSRF tokens to validate requests, enforce same-site cookie policies to prevent unauthorized requests.

2.4 Broken Authentication & Session Management

• Risks of weak authentication mechanisms leading to account takeovers sand unauthorized access.

• Mitigation: Enforce strong password policies, implement multi-factor authentication (MFA) and secure session management with short expiration times.

2.5 Security Misconfigurations

• Improperly configured security settings can expose applications to attacks.

• Mitigation: Regularly audit and update security configurations. Disable unnecessary services, default credentials and enforce least privilege access.

2.6 Insecure Deserialization

• Attackers exploit deserialization vulnerabilities to execute arbitrary code or escalate privileges.

• Mitigation: Use safe serialization formats, validate serialized data and restrict deserialization sources to trusted sources only.

2.7 Server-Side Request Forgery (SSRF)

• SSRF attacks allow attackers to manipulate server requests, potentially accessing internal systems.

• Mitigation: Restrict outbound requests to trusted domains, implement network segmentation to limit exposure.

3. Secure Development Practices to Prevent Application Attacks

• Secure coding principles (e.g., least privilege, defence in depth).

• Implementing automated security testing in CI/CD pipelines.

• Using security frameworks like OWASP Top 10 for proactive defence.

4. Conclusion

Understanding and mitigating application attacks is essential for securing software systems. By implementing secure coding practices, input validation and authentication controls, developers can reduce vulnerabilities and enhance application security. Encouraging developers to integrate security at every stage of development.

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Secure Coding Practices: Building Resilient Software

1. Introduction to Secure Coding Practices

• Why secure coding is essential for resilient software.

• The impact of insecure code on cybersecurity risks.

Introduction

Secure coding is a fundamental aspect of software development, ensuring applications are resistant to vulnerabilities and cyber threats. By following industry best practices, developers can minimize security risks and create robust, secure software.

2. Fundamental Secure Coding Principles

 

2.1 Least Privilege and Access Control

• Restricting permissions to minimize attack surfaces.

• Implementing role-based access control (RBAC).

Secure coding is guided by several key principles:

• Least Privilege – Grant users and applications only the permissions they need.

• Fail-Safe Defaults – Restrict access by default and allow only necessary permissions.

• Defense in Depth – Layer security controls to mitigate risks.

• Secure by Design – Integrate security from the start rather than as an afterthought.

2.2 Input Validation and Sanitization

• Preventing injection attacks through strict validation.

• Using allowlists and rejecting unexpected input formats.

Unvalidated input is a common attack vector. Developers must:

• Validate all user input to prevent SQL injection and command injection.

• Sanitize input to remove malicious characters before processing.

3. Secure Session Management

Sessions must be protected to prevent hijacking:

• Use secure cookies with the HttpOnly and Secure flags.

• Implement short session expiration times to reduce exposure.

2.3 Secure Error Handling

• Avoiding information leakage through detailed error messages.

• Logging errors securely without exposing sensitive data.

2.4 Memory Management and Buffer Security

• Preventing buffer overflows and memory leaks.

• Using safe functions and modern memory protection techniques.

4. Proper Error Handling

Error messages should be generic to avoid exposing system details:

• Log errors internally but display minimal information to users.

• Avoid revealing stack traces or database queries in error responses.

5. Secure Authentication and Authorization

Authentication mechanisms must be strong and resistant to attacks:

• Enforce Multi-Factor Authentication (MFA) for sensitive operations.

• Implement role-based access control (RBAC) to restrict permissions.

6. Common Secure Coding Techniques

Prevent Cross-Site Scripting (XSS) by encoding output before rendering it in a browser.

• Use HTML entity encoding to neutralize malicious scripts.

• Implement Content Security Policy (CSP) to restrict script execution.

7. Secure Code Review and Automated Testing

• Manual vs. automated code reviews for vulnerability detection.

• Integrating security testing tools into CI/CD pipelines.

8. Secure Code Reuse, Secure Software Supply Chain Management

Using trusted libraries and frameworks reduces security risks:

• Avoid third-party libraries with known vulnerabilities. Ensuring third-party libraries and dependencies are secure.

• Regularly update dependencies to patch security flaws.

9. Memory Management and Buffer Overflow Prevention

Improper memory handling can lead to buffer overflow attacks:

• Use bounds checking to prevent memory corruption.

• Implement safe memory allocation techniques.

10. Secure Coding Standards and Compliance

Organisations follow established standards to ensure secure development:

• OWASP Secure Coding Guidelines – Best practices for web applications.

• ISO/IEC 27034 – International standard for application security.

• NIST Secure Software Development Framework (SSDF) – Guidelines for secure coding.

Secure coding is essential for building resilient applications that withstand cyber threats. By following best practices, validating input, managing sessions securely and enforcing authentication controls, developers can reduce vulnerabilities and enhance software security. In short reinforce the importance of proactive security in coding and encourage developers to adopt secure coding as a standard practice.

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Cloud Computing: Security Considerations and Best Practices

1. Introduction to Cloud Security

Cloud computing has transformed the way organisations store, process and manage data, offering scalability, flexibility and cost efficiency. However, it also introduces unique security challenges, requiring robust security frameworks to protect sensitive information and ensure compliance.

2. Cloud Service Models and Security Implications

Cloud computing operates under three primary service models:

• Infrastructure as a Service (IaaS) – Provides virtualized computing resources, such as servers and storage.

• Platform as a Service (PaaS) – Offers development environments for building and deploying applications.

• Software as a Service (SaaS) – Delivers fully managed applications over the internet.

Each model has distinct security considerations, requiring access controls, encryption and monitoring to mitigate risks.

2.1 Infrastructure as a Service (IaaS)

• Security considerations for virtualized computing resources.

• Best practices for securing cloud-based infrastructure.

2.2 Platform as a Service (PaaS)

• Security risks in application development environments.

• Implementing secure coding practices in cloud-based platforms.

2.3 Software as a Service (SaaS)

• Data protection and access control in SaaS applications.

• Managing third-party risks and compliance requirements.

3. Cloud Deployment Models and Security Strategies

Organisations can choose from different cloud deployment models based on their security and operational needs:

• Public Cloud – Hosted by third-party providers, offering shared resources.

• Private Cloud – Dedicated infrastructure for a single organization, enhancing security.

• Hybrid Cloud – Combines public and private cloud environments for flexibility.

• Community Cloud – Shared infrastructure among organisations with similar security requirements.

3.1 Public Cloud

• Shared infrastructure risks and mitigation strategies.

• Implementing strong identity and access management (IAM).

3.2 Private Cloud

• Enhanced security controls for dedicated environments.

• Best practices for securing internal cloud infrastructure.

3.3 Hybrid and Multi-Cloud Security

• Managing security across multiple cloud environments.

• Ensuring data integrity and secure interoperability.

4. Key Cloud Security Challenges

Cloud environments introduce unique security risks, including:

• Data Breaches – Unauthorized access to sensitive cloud-stored data.

• Misconfigurations – Improper security settings leading to vulnerabilities.

• Insider Threats – Employees or contractors misusing access privileges.

• Compliance Issues – Meeting regulatory requirements across different jurisdictions.

5. Cloud Security Best Practices

5.1 Identity and Access Management (IAM)

• Implement Multi-Factor Authentication (MFA) for cloud access.

• Use role-based access control (RBAC) for cloud resources to restrict permissions.

5.2 Data Encryption & Protection

• Encrypt data at rest and in transit using strong cryptographic algorithms.

• Store encryption keys securely in cloud key management systems.

5.3 Secure Cloud Networking

• Use network segmentation to isolate sensitive workloads.

• Deploy firewalls and intrusion detection systems (IDS) to monitor traffic.

5.4 Continuous Monitoring and Threat Detection

• Implement Security Information and Event Management (SIEM) for real-time threat analysis.

• Use AI-driven security tools to detect anomalies and prevent attacks.

5.5 Compliance and Governance

• Ensure adherence to GDPR, HIPAA and ISO 27001 security standards.

• Conduct regular security audits and assessments to maintain compliance.

6. Conclusion

Cloud computing offers unparalleled advantages, but securing cloud environments requires proactive security measures. By implementing strong access controls, encryption, continuous monitoring and compliance frameworks, organisations can protect their cloud assets and mitigate risks. In short integrate security into cloud adoption strategies.

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