Remove upstream headers in envoy proxy after external authentication
What about using the route level option request_headers_to_remove to remove an Authorization header?
See https://www.envoyproxy.io/docs/envoy/latest/api-v3/config/route/v3/route_components.proto
Note that I am not an expert in envoy proxy, but from what I was able to find you can actually write a Lua script that would be able to remove the headers. In the documentation you can find an example of such script, and with a little bit of tinkering you should be able to customize it if needed:
-- Remove a response header named 'foo'response_handle:headers():remove("foo")You can find more information in the official documentation. Here for config.filter.http.lua.v2.Lua and here are the script examples.