Threat Modeling Inside Agile Sprints

While coaching a distributed product team, we kept discovering security issues after release because 'real work' trumped threat modeling. We needed a repeatable habit that fit inside two-week sprints without derailing velocity.

• Stories shipped without mapping attack surfaces.
• New SaaS integrations entered production without vetting.
• Secrets drifted between environments due to copy/paste configs.
• Incident response relied on ad-hoc tribal memory.

1. Introduced Security Acceptance Criteria on any story touching auth, payments, or PII; the story was 'incomplete' without it.
2. Ran 10-minute STRIDE huddles at sprint kickoff — designers, engineers, PMs call out spoofing/tampering risks while solutions are still cheap.
3. Baked secret scanning, dependency auditing, and SAST into CI; pull requests failed fast with actionable remediation steps.
4. Created lightweight incident playbooks + rollback paths so on-call rotations knew exactly how to respond when monitoring fired.
5. Tracked findings in Jira alongside product work so security debt stayed visible and estimable.

Within two sprints, late-stage security escalations dropped 48%, we caught three misconfigured OAuth scopes before launch, and the team stopped treating AppSec as an afterthought. Leadership kept the ritual permanently because it cost 10 minutes and saved weeks.

Security culture sticks when it feels like a design review, not a compliance audit. Embedding tiny, predictable rituals beats giant yearly checklists every time.