Most early startup breaches aren’t sophisticated. They’re predictable: a homegrown login, a leaked API key in a repo, a database exposed to the internet, or “we’ll add logging later.” Attackers don’t need genius. They need one cheap mistake and enough time to try it everywhere.
Authentication: Treat Login Like an External Dependency
If you’re not selling identity, don’t build identity. Use a proven provider such as Auth0, Clerk, or AWS Cognito and spend your engineering time on authorization rules and product logic. Homegrown auth is a magnet for bad sessions, weak password handling, and account enumeration.
If you still insist on owning it end-to-end, ship the boring essentials: password hashing with Argon2 or bcrypt, aggressive rate limiting on sign-in and password reset, long passphrases (and a blocklist for known-compromised passwords), MFA for admins, and secure sessions via HttpOnly, Secure cookies with sane expiration. No tokens in localStorage.
Encryption: Stop Thinking “HTTPS” Is the Finish Line
Start with TLS everywhere, including service-to-service traffic. If your internal calls are plaintext, you’ve built a sniffing-friendly environment the moment something lands in the wrong network segment.
Encrypt data at rest for databases and object storage, then go one step deeper for high-risk fields. For PII, secrets, access tokens, and anything regulated, use application-level encryption so a database snapshot or misconfigured read role doesn’t instantly become a breach.
Keys belong in a KMS (AWS KMS, Google Cloud KMS, Azure Key Vault). If your key sits next to the ciphertext in the same environment, you’ve mostly created encryption-flavored storage.
Infrastructure Security: The Boring Defaults That Save You
Least privilege isn’t a policy doc; it’s a set of permissions that fail closed. Keep production access narrow, time-bound, and audited. Put databases in private subnets. Use a VPC and security groups/network policies that assume every service will get probed.
Secrets shouldn’t live in environment files committed to a repo or pasted into a wiki. Use a secrets manager (AWS Secrets Manager, GCP Secret Manager, HashiCorp Vault) and rotate credentials on a schedule that matches your risk. Make dependency scanning and container/image scanning part of CI/CD so known-bad libraries don’t quietly ship.
| Framework | Best fit | Cost | Time |
|---|---|---|---|
| SOC 2 Type II | B2B SaaS with enterprise customers | High | Long |
| HIPAA | Handling U.S. protected health information | Medium to High | Medium to Long |
Incident Response: Decide Who Does What Before You’re Sleep-Deprived
An incident plan isn’t a PDF you “finish.” It’s a decision tree you can run at 2 a.m. Define how you detect issues (alerts, anomaly detection, WAF signals), who’s on point (engineering, security, legal, comms), and what changes by severity level (containment steps, customer impact, disclosure triggers).
Centralized logs are non-negotiable. If you can’t answer “what happened?” quickly from authentication logs, API gateway logs, database audit logs, and cloud control-plane logs, you’ll burn days guessing. Run tabletop exercises at least once a year and after major architecture changes.
Security Culture: Don’t Hire Smart People and Then Teach Them to Ignore Risk
The fastest way to lose security is to treat it as one person’s job. Train every engineer on the OWASP Top 10 and make the expectations concrete: parameterized queries, input validation, least privilege authorization checks on every sensitive action, and no “admin-only” endpoints without hard enforcement.
Here’s the uncomfortable standard: if a new engineer can deploy code on day one, they can also ship a vuln on day one. Your onboarding should cover secure coding practices, review checklists, and how secrets and access are handled.
Next action: open your production cloud console and answer three questions without guessing—(1) which identities can read your customer data, (2) where the encryption keys live, and (3) how you’d know if an attacker started enumerating accounts. If you can’t answer in minutes, fix that before you ship more features.
