Security Baked In: The OWASP Top 10 Checklist Every SaaS Needs

The OWASP Top 10 is the industry's consensus list of the most common and damaging web vulnerabilities. It's also the checklist your first real security review will use. Here's how each one shows up in a modern SaaS, and what to do about it.

1. Broken Access Control

The #1 cause of SaaS data leaks. Someone can access resources they shouldn't. Fix: enforce authorization at the data layer (not just routes), use row-level security for multi-tenant data, and write authorization tests per endpoint.

2. Cryptographic Failures

Plaintext passwords, weak hashing, unencrypted PII. Fix: bcrypt or argon2 for passwords, TLS everywhere, KMS-managed keys for field-level encryption of sensitive PII.

3. Injection

SQL injection is less common but XSS and command injection are still very much alive. Fix: parameterized queries only, output encoding on render, and never eval() user input.

4. Insecure Design

Whole categories of vulnerability come from architecture choices, not bugs. Fix: threat-model new features, especially anything touching auth, payments, or other tenants' data.

5. Security Misconfiguration

Default credentials, open S3 buckets, public dashboards. Fix: IaC with reviewed defaults, automated configuration scanning, and a "deny by default" posture on every new resource.

6. Vulnerable Components

Supply chain attacks live here. Fix: Dependabot or equivalent, pinned versions in CI, and a habit of reading release notes before updating critical packages.

7. Authentication Failures

Credential stuffing, weak MFA, predictable reset tokens. Fix: rate limiting on login, mandatory MFA for admin, and one of the mature IdPs (Cognito, Auth0, Clerk) rather than rolling your own.

8. Software & Data Integrity Failures

Unsigned code, unsigned updates, trusting user-supplied data for integrity decisions. Fix: signed artifacts in CI/CD, webhook signature verification, and immutable deploys.

9. Security Logging & Monitoring Failures

The median time to detect a breach is still months. Fix: centralized logs, alerts on anomalies (bulk data reads, admin actions, failed logins), and actually read the alerts.

10. Server-Side Request Forgery

Your app fetches a URL on behalf of a user, and that URL points at your internal network. Fix: allowlist egress destinations for any user-controlled URL fetch, and deny requests to metadata services.

The baseline we ship

Our SaaS Platform has defenses for all ten baked into the default configuration, because retrofitting security after launch is how most of this list ends up exploited in the first place.