API10:2023 — Unsafe Consumption of APIs

✅

Course Complete

You’ve finished all 10 modules of the OWASP API Security Top 10. Here’s what you learned in API10:

✓What API10 is: treating third-party API responses as inherently trustworthy — skipping the input validation, SQL parameterization, and output escaping applied to user data

✓Three failure types: CDN script compromise (Magecart), injection via third-party response fields (SQL, XSS, JNDI), and SSRF via redirect from a trusted third-party

✓Ticketmaster / Magecart / Inbenta (2018) — Inbenta’s CDN was compromised; the modified script ran on Ticketmaster’s payment pages for four months and stole 40,000 cards

✓Log4Shell (CVE-2021-44228) via third-party data — JNDI payloads in third-party API responses (geolocation, enrichment) triggered RCE in applications that logged the data without sanitization

✓The core insight: security controls belong at the point of use, not at the point of trust — parameterize SQL and escape HTML for all data, regardless of whether it came from a user or a vendor

✓Subresource Integrity (SRI) — the integrity attribute on script tags lets the browser verify CDN file hashes and block tampered scripts before they execute

✓Seven mitigations: treat responses as untrusted, validate all fields, allowlist outbound URLs, vendor due diligence, SRI for scripts, minimum-privilege integrations, isolate integration points

You’ve completed the OWASP API Security Top 10

From Broken Object Level Authorization (API1) to Unsafe Consumption of APIs (API10) — you’ve covered every major category of API security risk with real incidents, attack mechanics, and concrete mitigations. The goal wasn’t memorization. It was building a mental model for how APIs break, so you can recognize these patterns in the wild — in code you read, systems you design, and decisions you make. Every API you build or work with is more secure because you understand why it might not be.

← Back to Quiz ← Back to all modules