Apidor

Tool for automating the search for Insecure Direct Object Reference (IDOR) vulnerabilities in web applications and APIs.

Common payloads for uncovering IDOR vulnerabilities are created using a definition file which describes the API to be tested. The payloads are then sent to the corresponding endpoints, and any unexpected responses are highlighted for further investigation.

Definition file

The definition file is a YAML file that describes the API to be tested, as well as giving high and low privileged user tokens and other metadata. An example of a definition file is given below.

---
base: https://api.bncrypted.com
auth:
  header_name: Authorization
  header_value_prefix: Bearer
  high_privileged_access_token: f8h3qhwe48fh7w3874
  low_privileged_access_token: masdckjwf7h4iuhwqy3
vars:
  userId:
    high: 10001
    low: 10002
    alias: id
api:
  methods: [GET, POST, PUT, PATCH, DELETE, OPTIONS]
  headers:
  endpoints:
    users:
      - method: DELETE
        is_delete: true
        content_type: JSON
        headers:
        request_params:
        body_params:
          id: $userId
    users/$userId:
      - method: GET
        is_delete: false
        content_type: JSON
        headers:
        request_params:
        body_params:

• base: The base URL for the API
• auth.header_name: The name of the HTTP header for the authentication token
• auth.header_value_prefix: The prefix for the authentication token
• auth.high_privileged_access_token: The authentication token for the user with the highest privilege (aka. the victim)
• auth.high_privileged_access_token: The authentication token for the user with low privilege (aka. the attacker)
• vars: Variable values for high and low privileged requests to the same endpoint, accessed later in the file using $<var_name> syntax. For example, the high privileged user id of 10001 and the low privileged user id of 10002 can be accessed using $userId
• api.methods: Global HTTP methods used by all API endpoints
• api.headers: Global HTTP headers used by all API endpoints
• api.endpoints.<endpoint_name>.method: HTTP method for that endpoint
• api.endpoints.<endpoint_name>.is_delete: Whether the endpoint defines a delete instruction - the happy path test will not be run on this endpoint to preserve the resource (default: false)
• api.endpoints.<endpoint_name>.content_type: The content type of the data in the request body (application/json can be represented as JSON; application/x-www-form-urlencoded can be represented as FORM-DATA)
• api.endpoints.<endpoint_name>.headers: HTTP headers for that endpoint
• api.endpoints.<endpoint_name>.request_params: HTTP request parameters for that endpoint
• api.endpoints.<endpoint_name>.body_params: HTTP body parameters for that endpoint

Usage

$ go get github.com/bncrypted/apidor

$ apidor -d <definition_file>

$ apidor -h

  Usage of apidor:
  -cert string
    	Path to a local certificate authority file
  -d string
    	Path to the API definition YAML file (default "definitions/sample.yml")
  -debug
    	Specifies whether to use debugging mode for verbose output
  -e string
    	Specifies a single endpoint operation to test (default "all")
  -ignore-base-case
    	Specifies whether to ignore base case failure
  -o string
    	Log file name
  -proxy string
    	Gives a URI to proxy HTTP traffic through
  -rate int
    	Specifies maximum number of requests made per second (default 5)
  -tests string
    	Specifies which tests should be executed (default "all")

Test codes

Specific tests and combinations of tests can be specified using the tests flag (accepts single string or array of strings).

Code	Test	Description	Example
hp	High privileged	Tests using the high privileged variables with the high privileged access token (happy path test)	GET /users/10001
lp	Low privileged	Tests all variable permutations using the low privileged access token	GET /users/10001
np	No privileged	Tests all variable permutations without an access token	GET /users/10001 GET /users/10002
rpp	Request parameter pollution	Tests using parameter pollution on the request parameters	GET /users?id=10001&id=10002
bpp	Body parameter pollution	Tests using parameter pollution on the body parameters	GET /users id=10001&id=10002
mr	Method replacement	Tests endpoints using unexpected HTTP methods	PATCH /users/10001
rpw	Request parameter wrapping	Tests using parameter wrapping on the request parameters	GET /users?id=[10001] GET /users?id={id:10001}
bpw	Body parameter wrapping	Tests using parameter wrapping on the body parameters	POST /users {id: [10001]}
rps	Request parameter substitution	Tests using body parameters substituted as request parameters	POST /users?id=10001 {id: 10002}
rpspp	Request parameter substitution with parameter pollution	Tests using body parameters substituted as request parameters alongside parameter pollution on the substituted request parameters	POST /users?id=10001&id=10002 {id: 10002}
json	JSON extension	Tests using a .json extension on the URL	GET /users/10001.json
all	All	Runs all tests