report-writing

REPORT WRITING

Impact-first. Human tone. No theoretical language. Triagers are people.

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THE MOST IMPORTANT RULE

Never use "could potentially" or "could be used to" or "may allow". Either it does the thing or it doesn't. If you haven't proved it, don't claim it.

BAD:  "This vulnerability could potentially allow an attacker to access user data."
GOOD: "An attacker can access any user's order history by changing the user_id
       parameter to the target user's ID. I confirmed this using two test accounts:
       [email protected] (ID 123) successfully retrieved [email protected] (ID 456)
       orders, including their shipping address and payment method last 4 digits."

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TITLE FORMULA

[Bug Class] in [Exact Endpoint/Feature] allows [attacker role] to [impact] [victim scope]

Good titles (specific, impact-first):

IDOR in /api/v2/invoices/{id} allows authenticated user to read any customer's invoice data
Missing auth on POST /api/admin/users allows unauthenticated attacker to create admin accounts
Stored XSS in profile bio field executes in admin panel — allows privilege escalation
SSRF via image import URL parameter reaches AWS EC2 metadata service
Race condition in coupon redemption allows same code to be used unlimited times

Bad titles (vague, useless to triager):

IDOR vulnerability found
Broken access control
XSS in user input
Security issue in API
Unauthorized access to user data

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HACKERONE REPORT TEMPLATE

## Summary

[One paragraph: what the bug is, where it is, what an attacker can do. Be specific.
Include: endpoint, method, parameter, data exposed, required access level.]

Example: "The `/api/users/{user_id}/orders` endpoint does not verify that the
authenticated user owns the requested user_id. An attacker can enumerate any
user's order history, including PII (email, address, phone) and purchase history,
by incrementing the user_id parameter. No privileges beyond a standard free
account are required."

## Vulnerability Details

**Vulnerability Type:** IDOR / Broken Object Level Authorization
**CVSS 3.1 Score:** 6.5 (Medium) — AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
**Affected Endpoint:** GET /api/users/{user_id}/orders

## Steps to Reproduce

**Environment:**
- Attacker account: [email protected], user_id = 123
- Victim account: [email protected], user_id = 456
- Target: https://target.com

**Steps:**

1. Log in as [email protected], obtain Bearer token

2. Send the following request:

GET /api/users/456/orders HTTP/1.1 Host: target.com Authorization: Bearer ATTACKER_TOKEN_HERE

3. Observe response:

```json
{
  "orders": [
    {"id": 789, "items": [...], "email": "[email protected]", "address": "123 Main St..."}
  ]
}

The response contains victim's full order history and PII despite being requested by a different user.

Impact

An authenticated attacker can enumerate all user orders by iterating user_id values. This exposes: full name, email, shipping address, purchase history, and payment method (last 4). With ~100K users, this represents a mass PII breach affecting all registered users. Exploitation requires only a free account and takes minutes with a simple loop.

Recommended Fix

Add server-side ownership verification:

if order.user_id != current_user.id:
    raise Forbidden()

Supporting Materials

[Screenshot showing attacker's session returning victim's order data] [Video walkthrough if available]