OWASP Top 10 for SaaS: How AI Developers Prevent Attacks

The OWASP Top 10 — What Each One Means for Your SaaS

Let's go through each category with what it actually looks like in a SaaS codebase and the specific control that prevents it. This isn't an academic walkthrough — it's what a developer needs to check before every PR that touches a sensitive surface.

1️⃣ A01 — Broken Access Control

The #1 vulnerability for the past two OWASP cycles. In SaaS apps, it typically shows up as: a user reading or modifying another user's data by changing an ID in the request, horizontal privilege escalation where a member accesses admin endpoints, or CORS misconfiguration that allows cross-origin requests from untrusted domains. The fix: implement resource-level authorisation checks (does this user own this resource?), enforce RBAC at the middleware layer, and test with a secondary user account that shouldn't have access.

2️⃣ A02 — Cryptographic Failures

Storing passwords in plaintext or with MD5/SHA1. Transmitting sensitive data over HTTP. Using weak or hardcoded encryption keys. Storing credit card data when you don't need to. The fix: bcrypt or Argon2id for password hashing (minimum cost factor 12), TLS everywhere, AES-256 for data at rest, and a secrets manager for keys. Never store payment card data — use Stripe's tokenisation instead.

3️⃣ A03 — Injection (SQL, NoSQL, Command)

Still common in 2026, especially in AI-generated code where the model strings together queries using template literals. The fix: use parameterised queries or ORMs that handle escaping (Prisma, Sequelize, Knex). Never concatenate user input into a query string. For command execution, use child_process.execFile with argument arrays — not exec with a string. Add a SAST scanner to your CI pipeline to catch these automatically.

4️⃣ A04 — Insecure Design

This category is about architectural flaws — not implementation bugs. A password reset flow that doesn't expire tokens. An API that returns more data than the client needs. A multi-tenant app that doesn't isolate tenant data at the database level. These aren't caught by linters. They're caught by threat modelling before you build. The fix: run a lightweight threat model on every new feature — ask "how would an attacker abuse this?" before finalising the design.

5️⃣ A05 — Security Misconfiguration

Default credentials left unchanged. Debug mode enabled in production. S3 buckets set to public. Error messages that expose stack traces and internal paths. The fix: use infrastructure-as-code with security defaults (Terraform modules with secure defaults), add a security headers middleware (Helmet.js for Node.js), and scan your cloud configuration with a tool like AWS Security Hub or Prowler before launch.

6️⃣ A06 — Vulnerable and Outdated Components

Your dependencies have CVEs. All of them, eventually. The fix: run npm audit or Snyk in your CI pipeline on every build. Set up Dependabot or Renovate to automatically open PRs for dependency updates. Define a policy: critical CVEs patched within 7 days, high within 30 days. Track compliance. This is evidence your SOC 2 auditor will also want to see.

7️⃣ A07 — Identification and Authentication Failures

Weak passwords allowed. No brute force protection. Sessions that don't expire. Password reset tokens that are too predictable or long-lived. The fix: enforce a minimum password complexity, add rate limiting to login and password reset endpoints (10 attempts per 15 minutes is a reasonable default), expire sessions after 30 days of inactivity, and use cryptographically random tokens for password resets that expire after 15 minutes.

8️⃣ A08 — Software and Data Integrity Failures

Deserialising untrusted data. Using CDN scripts without subresource integrity checks. CI/CD pipelines that don't verify the integrity of build artefacts. The fix: add SRI hashes to any external scripts you load, use signed commits in your CI pipeline, and never deserialise user-supplied data into executable objects. JSON.parse is fine. eval() is not.

9️⃣ A09 — Security Logging and Monitoring Failures

Not logging failed login attempts. No alerting on unusual access patterns. Log files that are accessible to application code. The fix: log all authentication events, access control failures, and input validation failures. Set up alerts for: more than 10 failed logins from one IP in 5 minutes, any access to an admin endpoint from a non-admin account, and any error rate spike above your normal baseline.

🔟 A10 — Server-Side Request Forgery (SSRF)

Your app makes an HTTP request to a URL supplied by the user. An attacker passes an internal URL — like http://169.254.169.254/latest/meta-data/ (AWS metadata endpoint) — and your server fetches it, leaking cloud credentials. This is increasingly common in SaaS apps that have webhook, import, or integration features. The fix: validate and allowlist URLs before making outbound requests, block private IP ranges (10.x.x.x, 172.16.x.x, 192.168.x.x), and use a network egress proxy if possible.