Stop 10 · Application Security (AppSec)Topics · 1/9

Secure SDLC ('Shift Left')

In short

Finding a security bug the day before launch is painful and expensive. Shifting left means catching it while you code, when a fix is cheap and nobody is panicking.

Integrating security checks earlier in the development lifecycle (during coding and CI, not just before release) — 'shifting left' catches vulnerabilities when they're cheap to fix, not after deployment.

The blob site engineer inspects each floor of a rising building with a checklist.

Think of it like this

Checking the building as it rises

A wise site engineer checks the foundation and each floor as it is built, not after the whole tower is up. Fixing a crack early is simple; fixing it under a finished building is a disaster. Secure development checks security at every stage.

Watch it happen

Security at every stage

Design

Code

Build

Test

Release

1/5Think about threats while designing. A flaw in the plan is cheapest to fix now.

The big ideas

What you need to know

Earlier is cheaper

A bug caught at design costs a fraction of one found in production. Shifting left saves time and money.

Security at every step

Do not leave it to one final gate. Bake checks into design, coding, building and testing.

Everyone owns it

Security is not only the security team's job. Developers, testers and ops all share it in a secure SDLC.

Fast feedback

Quick, automated checks in the pipeline teach developers as they work, so the next bug never ships.

Save yourself the pain

Common mistakes

Oops

Leaving all security to one test right before launch.

Do this instead

Late bugs are costly and rushed. Spread checks across design, coding and building so issues surface early.

Oops

Treating security as the security team's problem alone.

Do this instead

In a secure SDLC, developers and ops share ownership. Shared responsibility catches far more than one gate.

Your mission

Add one early check

~30 min

Quick check

What does 'shift left' mean in a secure development lifecycle?

Go deeper

1Diagram a traditional 'security review at the end' process versus a shift-left approach.
2Learn why fixing a vulnerability in code review is far cheaper than fixing it in production.
3Identify one security check that could be added directly into a CI pipeline.