Software Engineering, ensuring security from the beginning of the software development process is essential. By establishing security requirements, you safeguard the end product against potential threats. Here is a guide on creating security requirements for your software project and when this should occur.
1. Understanding the Importance of Security Requirements
Security requirements define the necessary measures that ensure a software system’s confidentiality, integrity, and availability. They act as a bridge between high-level policies (e.g., “user data must be protected”) and technical details (e.g., “use AES-256 encryption for user data”).
2. When to Define Security Requirements
Ideally, security requirements should be defined during the early stages of the software development lifecycle (SDLC), preferably in the requirements gathering or analysis phase. This is because:
- Early detection of security issues reduces the cost of fixing them.
- It ensures that security is built into the system rather than added later.
- It provides a clear direction for the design and implementation teams.
3. Steps to Create Security Requirements
1. Understand the System and Its Context
Before defining security requirements, gain a comprehensive understanding of:
- The software’s purpose and functionality.
- The data it will handle and store.
- The environments in which it will operate (e.g., on-premises, cloud).
- The users and other systems it will interact with.
2. Identify Assets
List all assets (data, systems, hardware) associated with the software. Prioritize them based on their criticality and sensitivity.
3. Perform Threat Modeling
For each asset:
- Identify potential threats (e.g., unauthorized access, data breaches).
- Determine the possible vulnerabilities that could be exploited.
- Evaluate the potential impact of each threat.
Popular methodologies for threat modeling include STRIDE and DREAD.
4. Define Security Objectives
From your threat modeling, define high-level security objectives, such as:
- “Ensure data confidentiality.”
- “Maintain system availability.”
- “Protect against unauthorized access.”
5. Translate Objectives into Specific Requirements
- For each objective, derive concrete requirements. For instance:
- For data confidentiality: “The system shall encrypt user passwords using a salted hash algorithm.”
- For system availability: “The system shall achieve 99.9% uptime.”
- For unauthorized access protection: “The system shall implement two-factor authentication for all administrative accounts.”
6. Consider Legal and Compliance Requirements
Ensure your security requirements adhere to relevant legal and compliance standards like GDPR, HIPAA, or PCI-DSS.
7. Review and Revise
Collaborate with stakeholders, including security experts, to review and refine your requirements. This iterative process will help ensure completeness and feasibility.
8. Integration with Other Requirements
Ensure that security requirements are integrated with other project requirements to avoid conflicts and ensure a cohesive approach.
4. Continuous Re-evaluation
Security isn’t a one-time task. As the project progresses and the threat landscape evolves, revisit and update your security requirements. This might happen during:
- Design changes.
- New threat discoveries.
- Post-implementation, through periodic security assessments.
Attached to this message you will find a security requirements document for a product we already sell. Feel free to take it and customize it to fit your specific project needs
5. Security Checklist
If you are struggling about how to implement the security requirements, we prepared a FULL CHECKLIST for you on #CyberTechTalk WIKI.
Below these are a only few points which the every security specialist should take care about:
If you need more information about security in cloud, follow our previous posts.
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Thanks for the writeup. I took my CISM certification. CISM review manual ch 1 Security Governance states one must understand the business requirements ( above article step 1 – Understanding the Importance of Security Requirements ) . Next CISO is to identify the security requirements to meet the business requirements . Next CISO will analyse if the security requirements can be met by the current controls . In this case , there is a gap and identify initiative to develop software . Next go through the business case to get the initiative approved by senior management. The business case should state the scope , functional and security requirements
A project manager is assigned to initiate, plan, design, develop, test and implement the software. At this stage the security requirements should be known but can be fine tuned. The other steps mentioned are included in the project. Is my understanding correct ?
You are absolutely right! The implementation might differs from company to company.
First, please understand your organization’s process, then assess the assets.
After, establish plan and implement it.
Tune after all.
Repeat the process again and again.
Security industry is dynamic. This is a never ending battle between defensive controls against new vulnerabilities.