You could do the same thing with almost any type of app where you run your own web service; it's kind of a black box to the app market's test group...you could change everything but the domain name and security certificate (and most app stores don't pin the cert as they expire and you wouldn't want to recertify at every cert switch).

One thing Amazon or Google could do here for voice apps, though, that Apple and Google (Android) can't for standard phone apps, is audit voice responses for anomalies or user input that matches a suspicous pattern and flag apps that trigger it.

They can do this because every utterance a user sends a voice assistant passes through Amazon or Google systems. If an app has access to user PII, they could add some automation to flag suspicious user responses or anomalous activity that differs from x days previous and pass it up the chain for review.

One thing I do like about Alexa development is that if you, as a developer, are privacy-minded (and don't need nor want user data for anything), you can protect your users by configuring your apps not to collect any of your users' info . As a developer, you don't even get IP addresses as everything goes User > Amazon > Developer > Amazon > User.

You always get session and Amazon-assigned user id, but they're typically pretty anonymous unless the user says "I am Jane Doe" -- which, I guess we should be honest, probably does happen more than it should, and this is what the OP researchers are exploiting.

I don't know for sure about Google, but with Alexa skills are simply implemented as a web service. There is no way for Amazon to know that you've deployed new code on your web service. There are a lot of limits to what you can change though, the prompts / intents are specified in a manifest you have to upload. But what the device does for an existing intent, and the responses it sends, can be changed without their knowledge.

I just can't believe that people actually pay to have these things in their houses. Or maybe, sadly, I can.

A smartphone has a much larger attack surface and far more snooping capability.

A lot of people don't intentionally, Echo's get bundled with some BT internet packages in the UK.

It probably did prompt the second round review, but someone in head office is going too many reviews could lead to a congress led inquiry, so they stay quiet until a a contractor spills the beans on the nastiness happening behind the scenes.