Numeric parameter has no format defined

Issue ID: parameter-numerical-format

Average severity: Low

Description

Some numeric parameters in your API do not have the accepted format specified.

For more details, see the OpenAPI Specification.

Example

The following is an example of how this type of risk could look in your API definition. The parameter type is set to integer but the format is not specified:

{
    "parameters": {
        "type": "integer",
        "name": "total",
        "in": "query",
        "description": "Number of the objects in the array."
    }
}

Possible exploit scenario

If you do not specify an enforceable format of numeric values, attackers can try to send unexpected input to your backend server. This may cause the backend server to fail in an unexpected way and open the door to further attacks.

For example, the backend server could throw an exception and return a stack trace on the error. The trace could contain information on the exact software stack used in the implementation. This enables the attacker to launch an attack on specific vulnerabilities known in that stack.

Using your internal, company-specific formats is not currently supported.

Remediation

Define the format parameter for all numeric parameters. This ensures that only parameters of the expected format get passed to the backend.

Numeric parameters type integer can have the format int32 or int64. Numeric parameters type number can have the format float or double.

{
    "parameters": {
        "type": "integer",
        "name": "total",
        "in": "query",
        "format": "int32",
        "description": "Number of the objects in the array."
    }
}