Secure Software Development Lifecycle (SSDLC)

What SSDLC Means

SSDLC prevents vulnerabilities early instead of patching after breach.

SDLC: build and ship. SSDLC: secure by design through operations.

1) SSDLC Phases and Security in Each

A) Requirements Phase

Goal: make security measurable and part of definition of done.

• Define security requirements (auth, RBAC, tenant isolation, encryption, audit logs)
• Define NFRs (rate limiting, monitoring, backup/restore)
• Classify data (Public/Internal/Confidential/Highly Sensitive)
• Define compliance requirements (DPDP, GDPR, PCI, etc.)

Outputs: security checklist, data retention rules, abuse cases.

B) Design Phase

Goal: remove entire vulnerability classes before coding.

• Create DFDs and trust boundaries
• Perform threat modeling (STRIDE)

Outputs: threat model doc and architecture decisions for auth model, tenant isolation, tokens, secrets, logging.

C) Development Phase

Goal: secure coding by default (OWASP-focused).

• Input validation (type, length, format)
• Output encoding (XSS prevention)
• AuthZ and ownership checks on every request
• Safe DB access (parameterized queries / safe ORM)
• No hardcoded secrets; use vault/secret manager
• Least privilege service identities
• Safe error handling (no stack traces/secrets)
• Rate limiting for auth/OTP/webhook endpoints
• Secure file upload handling
• Deny by default

Definition of done: every endpoint has authentication, authorization, validation, safe logging, and access-control tests.

D) Build and CI Phase

Goal: automated security gates in every pipeline run.

• SAST
• SCA
• Secret scanning
• IaC scanning
• Container image scanning
• Security unit tests
• Policy-as-code checks

Outputs: signed artifacts and SBOM.

E) Testing Phase

• DAST
• Manual logic testing (IDOR, tenant bypass)
• Fuzzing
• Security regression tests
• Periodic pentesting

F) Release and Deployment Phase

• Separate dev/stage/prod environments
• Least privilege deploy roles
• Secrets from secret manager only
• WAF and gateway rate limits
• Secure headers (CSP, HSTS where relevant)
• Private DB networking
• Logging and alerts enabled before go-live

G) Operations Phase

• Central logging and alerting/SIEM
• Alerts for suspicious login, escalation, mass export, secret access
• Regular patching
• Backup restore drills
• Incident response runbooks

2) SSDLC Controls Map

3) Where Coding Agents Fit in SSDLC

AI coding agents increase speed and can also increase security risk if unmanaged.

A) Key Risks

• Prompt injection
• Secret leakage
• Supply chain risk from unsafe dependency additions
• Unsafe code generation (auth bypass, TLS disable, weak validation)
• Data/IP leakage in prompts
• Over-privileged agent accounts

B) Secure Agent Usage

• Least privilege and short-lived tokens for agents
• Sandboxed runtime (isolated container/VM, restricted egress)
• No-secrets policy with automated secret scanning
• Mandatory review + tests + security checks before merge
• Dependency allowlist + SCA/license checks
• Prompt hygiene (no PII, no prod secrets/logs)
• Traceability of agent changes/prompts/checks

C) Agent-Aware CI/CD Gates

• Block immediately on secret detection
• SAST + SCA mandatory
• Policy checks to prevent disabling auth/rate limits
• Human approval required for high-risk files (auth/IAM/payment/tenant/infra)

4) Practical SSDLC Pipeline

On Every PR

• Lint and unit tests
• SAST
• SCA
• Secret scan
• IaC scan (if infra changed)
• Container scan (if Docker/image changed)
• Mandatory human review
• Merge only if all checks pass

Nightly

• DAST against staging
• Dependency updates and patch checks

Before Production Release

• Threat model updated for major changes
• Targeted manual test/pentest for critical modules
• Backup restore verification and runbook readiness

5) Workshop Closing Message

SSDLC moves teams from "We will fix security later" to "Security is part of how we build."

Agents increase speed. SSDLC ensures safety.