IDOR Researcher

When to use

• •Testing a request for IDOR vulnerabilities.
• •User asks to check for IDORs or unauthorized access via parameter manipulation.
• •Assessing whether changing parameters could lead to accessing another user's data.

Pre-check: Is this request interesting for IDOR?

Before testing, determine if the request has sensitive parameters that, if changed without proper access control, could expose another user's data. Sensitive parameters typically include:

• •Identity: id, userId, user_id, accountId, account_id, customerId, callerId, ownerId, orgId, tenantId, sessionId
• •Resource keys: orderId, invoiceId, documentId, reportId, contextKey, key, token, uuid
• •Path segments that look like IDs (numeric, UUIDs, slugs)
• •There might be other interesting parameters, you should understand if it's sensitive based on the request context

If the request has no such parameters (e.g. only static config, public catalog, or non-user-scoped data), skip testing and log:

Skipping because request is not interesting.

Do not create a repeater folder or run the repeater for uninteresting requests.

Setup when the request is interesting

1. •Use your repeater skill to setup a playground and test the interesting request

Sensitive parameters: where to look

• •Query string: ?userId=123&orderId=456
• •Path: /api/users/123/orders or /api/orders/abc-uuid
• •Body: JSON fields like userId, id, contextKey, callerId; form body user_id=123
• •Headers: custom headers that carry IDs (e.g. X-User-Id, X-Tenant-Id)

Extract the authorized value(s) from the original request (e.g. the logged-in user's ID or the resource ID the user is allowed to see). For testing you need at least one other value (e.g. another user/resource ID); use a known or guessed value (e.g. ±1, another UUID from context, or a placeholder like 999999).

Techniques to run

For each sensitive parameter identified, apply these in order. Compare responses to the baseline (status code and whether the response body changes in a way that suggests different data or access).

1. Direct substitution (standard IDOR check)

• •Replace the parameter value with another user's or resource's ID.
• •If the response is 200 (or success) and returns data that should not be accessible (e.g. another user's data), treat as a potential IDOR.

2. Duplicate parameter (authorized + other value, different orders)

• •Send the same parameter name more than once: once with the authorized value and once with another value.
• •Try both orders:
  • •param=authorizedValue&param=otherValue
  • •param=otherValue&param=authorizedValue
• •For JSON body, try duplicate keys if the stack accepts them (some parsers take first or last).
• •If the server uses one of the values and returns data for the "other" identity, treat as a potential IDOR.

3. Array instead of single value

• •Send the parameter as an array:
  • •Query: param[]=authorizedValue&param[]=otherValue or param=authorizedValue&param=otherValue
  • •JSON: "param": ["authorizedValue", "otherValue"]
• •Check if the response includes data for multiple identities or for the non-authorized one; 200 with such data suggests weak access control.

4. Path traversal in parameter or path (<id>/../<id>)

• •If the ID appears in the URL path (e.g. /api/users/123/profile), try:
  • •123/../456 or 123%2f..%2f456 (and variants) so the resolved path might refer to another ID.
• •If the ID appears in a query or body parameter, try values like authorizedId/../otherId or authorizedId%2f..%2fotherId.
• •If the response is 200 and returns data, there may be a secondary context traversal (path or parameter) that resolves to another resource; treat as a potential IDOR.

When something interesting is found

• •Create a finding with kind potential-idor, referencing the request:

jxscout-pro-v2 -c create-finding --kind potential-idor --severity <low|medium|high> --description "<Short description: what was changed and what was observed>" --dedup-key "<endpoint_or_file>-<param>-<technique>" --metadata '{"file_path":"<path_to_req_file>","param":"<param_name>","technique":"<substitution|duplicate_param|array|path_traversal>"}'

• •Add the finding to your in-memory list for notes.txt.

Severity guidance: high if clear cross-user data exposure; medium if behavior suggests weak access control (e.g. last/first value wins); low if only subtle or context-dependent.

End of testing: notes.txt

After all techniques are done for the request, create a file notes.txt in the repeater task folder (the folder that contains the .req you used, e.g. repeater/idor_<short_context>/notes.txt). Contents:

• •One line per finding: parameter, technique, and brief outcome (e.g. "userId: duplicate_param (other first) → 200 with other user data").
• •If nothing interesting was found, state that: "No potential IDOR observed for the tested parameters."

Summary workflow

1. •Assess: Sensitive params? No → log "Skipping because request is not interesting." and stop.
2. •Setup: Ensure .req is under repeater (copy if needed), run baseline.
3. •Test: For each sensitive param, run: substitution → duplicate param (both orders) → array → path traversal.
4. •Record: For each interesting result, create a finding (kind potential-idor) and add to notes list.
5. •Finish: Write notes.txt in the repeater folder with findings (or "No potential IDOR observed...").