The Secure Software Development Life Cycle: Syncing Development and Security

Over the last five to 10 years, the nature of software development has shifted dramatically. Whereas large software releases occurred every six to 18 months in the past, current release schedules have become much more frequent. The waterfall model of software development has morphed into what we now know as the DevOps model.

As a consequence, DevOps has instigated changes in the traditional waterfall security touchpoints. In essence, DevOps has changed the very nature of how application security needs to be implemented. To avoid friction in the development process, application security activities must be adapted to the new world of DevOps practices. It has to go beyond the basics of threat modeling, design review and two weeks of pen testing.

Under DevOps, some development organizations now do software releases on a daily, weekly or bi-weekly cadence. But they’re still grappling with older application security models. As a result, development and security testing can be out of sync—you cannot conduct a two-week pen test on software that’s released weekly. These organizations need effective security assurance in their SDLC that’s good, quick, early and—above all else—automated.

The Changing Nature of Software Development

The way software is developed keeps changing. And it keeps accelerating. Application security needs to change to catch up. Automation will play a key role in enabling application security to maintain the pace of DevOps. DevOps needs automation to effectively deal with software release cadences that occur on a daily, weekly and bi-weekly basis as well as to increase agility generally within the SDLC.

For example, DevOps accelerates when the automated pipeline embeds application security scanning into pre-commit checks. In this way, consistent levels of application security testing apply every time developers check in code, resulting in a fully automated check-in process. But automation doesn’t lock developers into the same level of security for every code change. For example, if the change only involves altering the color of a logo, heavy security scanning and manual won’t be necessary. At least not the way it would be if the application is accessing sensitive data.

So, instead of giving developers quarterly SAST results, automation puts the code analysis right there in front of developers as they’re checking in code (via certain IDE plugins). Presenting the code analysis findings to developers, while they are still in the code, has several advantages:

• The code is still fresh in the developers’ minds.
• Coding problems can be caught earlier and more easily while developers are still thinking about the code.
• It mitigates the risk of developers not remembering the code context at a later date.

Overall, the more automation there is in application security the better it is for open source validation, container scanning containers, QA testing, API security and more.

Automated Security Assurance and Out-of-Band Activities

When it comes to implementing testing in DevOps, you must balance automated security assurance with out-of-band activities. That means it’s sometimes appropriate to slow down the automated security process. Even in a completely automated DevOps process you may need to slow down to make necessary changes. It’s true a code change, such as just changing the background color on a web app, may not be too risky. There’s no problem with automating that DevOps step and pushing out the change. But, if your web app interacts with customer data, you’d be prudent to slow down and take the next application security test out of band, and make sure you’ve got the procedure right because it’s much riskier.

There are different levels of risk and severity within each release of an application. Development organizations need to accept this and adapt to each release’s potential risk and severity level. Then, they need to provide the appropriate level of security assurance and security coverage, whether that is automated within the DevOps workflow, performed out of band or some combination of the two.

Life in the Fast Lane

For DevOps organizations, one of two avenues beckons to them: the security express lane or the security slow lane. You could create an automated DevSecOps process across the development organization—the security fast lane. But, there’s no one-size-fits-all DevSecOps process for enterprises. That’s because there could be up to hundreds of development teams within an enterprise. And there’s not always a standardized process that all dev teams can follow. It’s a challenge to adapt automated security to each development team. Those in the security fast lane should use a security champion to work with the development team and be the point person to assist them with understanding application security needs and remediation guidance.

In the security slow lane, individual development teams may still be enabled to go fast. The difference is that they will pick the SDLC tools that make the most sense for that team. Then, they should also pick the application security tools that make the most sense for them. The bottom line for organizations is that application security needs to involve an acceptable level of friction for developers to make DevSecOps work. If there is too much friction, developers will bypass application security in favor of expediting coding activities.