You can use information from all of your Akto dashboard in your YAML test.

Simple API Security testing involves fuzzing API with standard wordlists. However, to make testing really powerful, you'd need real data from your application. Eg. instead of trying incremental user_id=1, user_id=2, user_id=3, etc., you would want to try with user_ids that actually exist in your system eg. user_id=3489, user_id=3259.

Contexts will help you query all your data from Akto dashboard - which you can then use in your YAML tests.

Akto supports 4 types of contexts -

  1. Roles (roles_access_context) - You can access tokens from Test roles that you have configured in the dashboard

  2. API Inventory (endpoint_in_traffic_context) - You can use this context to check if an endpoint already exists in API Inventory. This is useful while discovering shadow APIs. An endpoint is a shadow endpoint only if it exists and is NOT being used by the application.

  3. Parameters (param_context) - You can use this context to query all parameters (JSON/form-data etc.). For example, you want to run a BOLA test that tries to access cart details by changing cart_id parameter in the request body. You can use param_context to query all keys that match .*cart_id.* and use this wordlist in your BOLA test.

  4. Private variable (private_variable_context) - You can use this context to find out if a particular value is being used by exactly 1 user or multiple users. A cart_id or a transaction_id is particular to a user, whereas product_id can be queried by multiple users

Roles access context

Once you create a Test role in Akto dashboard and configure auth tokens for that role, you can use the auth tokens in your YAML test.

Example - You want to test each admin API if they can be accessed using a member token. To carry out this test, you can create a role called MEMBER_TOLE . You would also have to add auth token to the role (eg Authorization: Bearer member.role.token) . You can now use it in your YAML to replace the auth token header.

Sample YAML -

    contains: "/admin"
  type: single
    - req:
      - modify_header:
          ${roles_access_context.MEMBER}: 1       
    gt: 200
    lt: 300          

This YAML runs only on endpoints that contain /admin (assuming these are admin APIs). It replaces the auth token in the original request by MEMBER auth token. If the response is 2xx, it is a vulnerability

API Inventory context

You can use this context to find out if an endpoint exists in API Inventory.

Example - You want to fuzz and find out all shadow endpoints which are NOT a part of API Inventory already.

    - req:
        modify_url: ${url}/${fuzzWords}
    gt: 200
    lt: 300
  endpoint_in_traffic_context: false   
  # raise Shadow-endpoint-found vuln only if the fuzzed endpoint is NOT in API Inventory

Parameters context

You can query all if your API traffic to extract list of user_id. You can extract this info in a variable (eg user_context). Say your API traffic contains the following parameters (across payloads, query params etc.) -

  • user: 23

  • user: 89

  • user_id: 56723

  • customer: 78193

You can then use user_context.key and user_context.value

    param: user|customer    # find all user or customer values from API traffic.
    extract: user_context
  type: single
    - req:
      - add_query_param:
          user_context.key: ${user_context.value} # add query param user=123 

This will fire 4 API calls - with the following query param one by one -

  • user=23

  • user=89

  • user_id=56723

  • customer=78193

Private variable context

You can use this context to find out if a particular value is being used by exactly 1 user or multiple users. Consider an e-commerce application (eg juice-shop).

Example of a public variable - The product-details of sku_id 9 is fetched using /api/v1/product?sku_id=9 . It is accessible by all users. We can validate it from the traffic also. Multiple users will be accessing the same endpoint - /api/v1/product?sku_id=9 successfully. Here sku_id is sort-of a public variable because all products can be accessed by all users.

Example of a private variable - Imagine a similar scenario, but for cart_id this time. The cart details of cart_id 98 are fetched using /api/v1/cart?cart_id=98. Unlike product_id, cart_id should NOT be accessible by more than 1 user.

Akto can differentiate between the usage behavior of cart_id and product_id. Akto will classify cart_id as private and product_id as public.

Note that private vs public variable depends a lot on traffic. These work very well if you are using automated traffic connectors. If you connect your staging or prod server, Akto will receive traffic from multiple users across several sessions that really improves this private vs public classification. If you are using BurpSuite, Postman etc., it is very likely that they contain only 1 user's data. The result in that case aren't good.

Say, you want to test APIs that use private variables (eg /api/v1/cart/123, /api/v1/order/78 etc.) for BOLA vulnerability. Simply replace the auth header by an attacker token (note that running the same test on /api/v1/product/9 will give a false positive and should NOT be tested for BOLA)

    gt: 0
  type: single
    - req:
          replace_auth_header: true

This will exclude /api/v1/product/9 and filter only cart and order APIs - /api/v1/cart/123, /api/v1/order/78.

By default, all variables are considered to be private. Only with more data (from multiple users across several sessions), Akto will start marking some variables as private.

You can also associate other operators such as regex: ".*user.*" - to filter only those vars that contain the string user.

Last updated