The Software Development Lifecycle (SDLC) encompasses several stages that take software from an idea in the heads of product managers to a working software product in the hands of an actual customer.
In traditional software development processes, and even in the modern agile development cycle, security was an afterthought. Organizations went through the elaborate process of creating a software product, only to realize at the end that the product may have security issues that need to be addressed.
These security issues may require changes to code, replacement of open source components, or other changes that may be complex or expensive to perform, and can delay the release of a product to the market. Even worse━due to market pressures, some organizations can end up releasing a product even though the security issues were not fully addressed.
A Secure SDLC is a development cycle that takes security into consideration from day one. All stages of the SDLC, from planning and design to development, testing and deployment, involve security considerations and are performed under the guidance or active inspection of security professionals. This can provide improved security at a much lower cost━because security is baked into applications from the get-go.
Almost all software projects, regardless of the specific development methodology, go through the following general stages:
- Planning━identifying the need for the product, the basic capabilities it needs to provide, who are the users and their specific requirements and prioritizing functionality.
- Design and architecture━defining how the requirements will be translated into actual software, including technology components, software architecture, integration with third-party components, data management and UI/UX.
- Development━writing the code and bringing the software to a stage where at least part of the functionality is working and can be tested.
- Testing━manually evaluating the software, or running automated tests, to ensure that it can really satisfy user needs in terms of required functionality, usability and performance.
- Deployment━taking a finished product and installing it in the actual environment where it will be used━by customers in their homes or by organizations for on-premise software, or in a data center for software offered in a cloud model.
- Production━running the application in production, ensuring that user are able to use it, and fixing operational problems as they occur.
How to Achieve a Secure SDLC
Here is how to work security into each of the stages of the SDLC, and transitioning to a true Secure SDLC.
Adding security to the planning, design and architecture stages
Identify security requirements right at the beginning of the SDLC, and train developers to identify vulnerabilities and security holes early on. A good choice of architecture or components can go a long way towards achieving security, whereas wrong architectural choices can require complex fixes or workarounds in later stages.
Evaluate hardware and software you will use in the development, testing and production stages and understand their known vulnerabilities, and the ability to patch and update them if vulnerabilities are discovered in the future.
Adding security to the development phase
Today’s developers rely heavily on open source components when developing software. Developers need knowledge and guidance on how to check if open source components are safe to use, and which specific versions might contain vulnerabilities. This can be done via automated tools such as SAST or Software Composition Analysis. They also need to be trained in security best practices such as input sanitization, encryption of sensitive data, and strong authentication.
Code reviews by peers or security experts working closely with the development team can have a major impact on the security competencies of developers. Very often, developers will introduce a security vulnerability out of habit or without realizing it. Having a peer review their work and suggest practical security fixes can improve security with a relatively small ongoing effort by developers.
Adding security to the testing phase
Train your testers to think like a hacker and add tests that look for or expose security vulnerabilities, such as code injection, cross-site scripting, session management problems, and insecure redirections.
Testers can use tools to scan applications and attempt various attacks, much like hackers would do in a production environment. Manual penetration testing is also tremendously useful in uncovering vulnerabilities or gaps in the software’s security posture and can be conducted in tandem by security staff and testing experts. Using Dynamic Application Security Testing (DAST) tools can help uncover insecure patterns in application code and resolve them.
Whether you deploy your application on-premises, on customer premises or in the public cloud, there are always security considerations. Consider the full environment in which software will be deployed, and the risks customers will be exposed to.
Understand the responsibility of different parties━for example, your organization, your cloud provider and your customer. Ensure you are covering your bases, test to ensure that cloud providers are actually providing the security measures promised, and adequately notify customers about security measures they are responsible for, such as using secure passwords.
Security is a core pillar for all software products and applications. Security testing in the software development lifecycle makes sure that applications go to the market without security weaknesses that attackers can potentially take advantage of.
Standardizing and outlining SDLC makes it easier for your security team to integrate security into the entire process. Steps to achieve a secure SDLC should be packaged for easy implementation. Once developers have a concrete understanding of all that needs to build security into applications and products, the realization becomes simple.