> For the complete documentation index, see [llms.txt](https://cortex-docs.paloaltonetworks.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://cortex-docs.paloaltonetworks.com/appsec-rules/iac-security/iam/appsec-openapi-14.md).

# Operation Objects Uses 'Implicit' Flow misconfiguration detected in code

## Rule Details

|                        |                        |
| ---------------------- | ---------------------- |
| Cortex AppSec Rule ID  | APPSEC\_OPENAPI\_14    |
| Category - Subcategory | Public Exposure - APIs |
| Provider               | OTHER                  |
| Severity               | MEDIUM                 |
| Framework              | OpenAPI                |

## Impact

This rule is checking for the usage of 'implicit' flow in operation objects within OpenAPI 2.0 files. The 'implicit' flow is an authorization method used in OpenAPI operations which has since been deprecated due to inherent security vulnerabilities. It relies on redirection-based flows that make an application more susceptible to access and refresh token interception. When these tokens are stolen, a malicious actor can impersonate a user and conduct activities without consent. Therefore, using a more secure method like 'authorization code' flow is recommended, which adds an additional layer of security and prevents direct exposure of tokens. The rule thus helps in maintaining good API security practices in the OpenAPI specifications.

## How to Fix

To fix this issue, you will have to specify a maximum number of items for each array in your API's schema definition.

## The above code is secure because it ensures that there is a limit on the number of items that can be returned in a response from the "/temperatures" endpoint. Without this limit, larger-than-expected responses could lead to performance issues or even application crashes. openapi: "3.0.0" info: version: "1.0.0" title: "An API for temperature measurements" paths: /temperatures: get: responses: "200": content: application/json: schema: type: "array" maxItems: 10 items: $ref: "#/components/schemas/Temperature" components: schemas: Temperature: type: "object" properties: id: type: "string" value: type: "number"


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