API › Module 8 › Lesson 3
Batching and Field Authz
Batching/aliasing can amplify abuse — rate limit and authorize fields.
Visual · api_batching_authz
Batching without limits is a force multiplier. Original Cyberlium.
Opening
One HTTP call can ask a hundred questions.
Query batching and aliases can bypass naive rate limits or pull nested data. Pair rate limits with field authz. No abuse against stranger graphs.
1. Batching risk
Many operations in one request. Costly resolvers multiply.
Limit depth, complexity, and batch size.
Command guide
Try these commands — Batching risk
═══ TOOLS & WEBSITES ═══ Browse / read these (authorized learning only — stay in YOUR lab / program scope)
GraphQL batching — https://cheatsheetseries.owasp.org/cheatsheets/GraphQL_Cheat_Sheet.html Authorization — https://cheatsheetseries.owasp.org/cheatsheets/Authorization_Cheat_Sheet.html
═══ INSTALL ═══
Linux (Debian/Ubuntu):
Command — copy this
sudo apt install curl
macOS: Built-in
Windows: Built-in (PowerShell: Invoke-WebRequest)
═══ LINUX / macOS ═══
Command — copy this
curl -sS -X POST http://127.0.0.1:8817/graphql -H "Content-Type: application/json" -H "Authorization: Bearer userA" -d '[{"query":"{ me { id } }"},{"query":"{ items { id } }"}]' | jq 'length // .'
curl -sS -o /dev/null -w "deep query %{http_code}
" -X POST http://127.0.0.1:8817/graphql -H "Content-Type: application/json" -d '{"query":"{ items { id owner { id owner { id } } } }"}'Primary tools to practice this lesson: curl. Reference sites: GraphQL batching (https://cheatsheetseries.owasp.org/cheatsheets/GraphQL_Cheat_Sheet.html); Authorization (https://cheatsheetseries.owasp.org/cheatsheets/Authorization_Cheat_Sheet.html). Run every command in the box — install first, then the usage lines — only on YOUR lab / program scope.
2. Field authz
Sensitive fields need checks even inside nested selections.
BOLA appears as nested object IDs.
3. Defenses
Persisted queries, depth limits, cost analysis, authz middleware.
Implement on YOUR services — do not DoS public demos.
4. What you ship: batching + field authz notes
Limits + field checks. No stranger abuse.
5. What you record before the next lesson
Defense list written.
6. Wrong vs right: stranger APIs vs literacy on systems you own
Worked failure — same API word, opposite target. Right never needs a live shop or classmate token.
Wrong
Alias-bomb a public GraphQL for fun.
Right
Write defenses. Next: GraphQL lab.
Mission: batching defense list
1) Name depth/complexity limits. 2) Name field authz. 3) Refuse stranger abuse.
Stuck? Ask Cyberlium AI Mentor
Ask Mentor: “What is query depth limiting?”
Knowledge Check
APPLY: Depth limits help:
Multiple choice
Knowledge Check
APPLY: True or False: Field authz is optional if the query is complex.
True or False
Knowledge Check
APPLY: Batching can bypass:
Multiple choice