ASP .NET Core custom authentication middleware for specific routes

Question

I have an ASP .NET Core application that is currently using an Authentication schema for JWTs where it checks the "Authorization" header for Bearer token in the form of a JWT and then build an Identity from that. This is the primary Authentication schema we want to use on this service, but there is a single MVC Controller endpoint that I want to use Basic Authentication instead. This endpoint is going to get hit by a WebHook from a client we don't have control over. That 3rd party client uses Basic Authentication as the only means of Authentication, so we are forced to use it.

After some googling, it appears Basic Authentication isn't supported natively in ASP .NET Core because of its vulnerabilities, but we are needing to use it because that is all our 3rd party webhook client supports.

After reading documentation about Authentication and Authorization on MSDN I am just confused on how I can configure this easily. It seems like something pretty simple, but there are lots of concepts here that I haven't worked with before like AuthorizationHandlers , Policies , AuthenticationMiddleware , etc. The other aspect is I am not sure how to make it so this is the only route that uses this Authentication schema.

Can someone point me to the right direction of what construct in ASP .NET I should be using to enforce Basic Auth on a single route. It would be best if I could use an Attribute on the route method to indicate that it should use Basic Auth like this:

[HttpGet]
[BasicAuthentication]
public async Task<IActionResult> Test([FromBody] string foo)
{
     return new OkResult();
}

OR

[HttpGet]
[Authorize("Basic")]
public async Task<IActionResult> Test([FromBody] string foo)
{
     return new OkResult();
}

I'm just not sure where to begin