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iMessage Preview Problems; leak your location by receiving a text message

theantisocialengineer.com

31–40 of 51 posts

Re: iMessage Preview Problems; leak your location by receiving a text message

#31
post #24

Sending the requests from the client is probably not the most secure idea. Requests should be proxied through a cloud server on Apple's end to reduce the security risk of these previews.

As has been pointed out below, iMessages are end-to-end encrypted so Apple has no way to read the URL to proxy it.

[deleted]

Re: iMessage Preview Problems; leak your location by receiving a text message

#32
post #24

Sending the requests from the client is probably not the most secure idea. Requests should be proxied through a cloud server on Apple's end to reduce the security risk of these previews.

As has been pointed out below, iMessages are end-to-end encrypted so Apple has no way to read the URL to proxy it.

[deleted]

Re: iMessage Preview Problems; leak your location by receiving a text message

#33
post #21
post #12

imessage won't auto-load previews until you ask it to do it the first time.

But there is no way to disable this once you have accepted it. I do not actually remember having been given the choice but it has been some time so I probably just do not remember. Ideally one could enable previews only from contacts.

correct - i couldn't find a way to disable if you've changed your mind.

Re: iMessage Preview Problems; leak your location by receiving a text message

#34
post #24

Sending the requests from the client is probably not the most secure idea. Requests should be proxied through a cloud server on Apple's end to reduce the security risk of these previews.

As has been pointed out below, iMessages are end-to-end encrypted so Apple has no way to read the URL to proxy it.

The client can still ask the Apple server for the metadata, since Apple already knows your IP from the push notification channel anyway. Ideally Apple would ensure that this lookup is not logged or stored in any way so there's no repository of the links people have sent to you anywhere.

Re: iMessage Preview Problems; leak your location by receiving a text message

#36
post #15

Earlier quoted context omitted.

Messages are end-to-end encrypted in iMessage, meaning Apple cannot read the message contents. This solution would require Apple to bypass that encryption for URLs (which are often privacy-sensitive). A good approach would be for the sender to fetch the URL and embed the preview as metadata along with the message. The only downside is that the sender could spoof the preview, but I think that's an acceptable trade-off…

No need to do in transit. I mean iMessage could simply proxy all http/https requests post decryption in iMessage, pre-request. At the end of the day this privacy trade off (apple gets your browsing info) is probably more secure than an embedded webview that could potentially be exploited and is auto-loaded. Similar to how Chrome alerts of malicious sites...I see this as a long term larger attack vector than privacy l…

The URL being disclosed to Apple was what I was getting at, which would happen with any approach that involves Apple performing the request on behalf of the user. I don't think the trade-off you're describing is necessary given that the sender could prepare the preview.

Re: iMessage Preview Problems; leak your location by receiving a text message

#37
post #24

Earlier quoted context omitted.

As has been pointed out below, iMessages are end-to-end encrypted so Apple has no way to read the URL to proxy it.

You could still have the client use Apple as a proxy. This would reduce the privacy of the message but only the URL and only exposing it to specific service at Apple. If it is a SOCKS proxy, you could reduce the exposure to just the IP address and some amount of leakage to whatever DNS server the phone is using.

Why not have the sender do that work so Apple can just stay out of it?

Re: iMessage Preview Problems; leak your location by receiving a text message

#38
post #37

Earlier quoted context omitted.

You could still have the client use Apple as a proxy. This would reduce the privacy of the message but only the URL and only exposing it to specific service at Apple. If it is a SOCKS proxy, you could reduce the exposure to just the IP address and some amount of leakage to whatever DNS server the phone is using.

Why not have the sender do that work so Apple can just stay out of it?

The sender could be a dumb SMS client. I'd be happy to just turn off previews entirely.

Re: iMessage Preview Problems; leak your location by receiving a text message

#39
post #30
post #24

Earlier quoted context omitted.

As has been pointed out below, iMessages are end-to-end encrypted so Apple has no way to read the URL to proxy it.

The client could send the request to Apple though, and pass the URL through that way, instead of requesting the actual URL. There's a trade-off there though that Apple gets to see all the links being sent over iMessage.

> There's a trade-off there though that Apple gets to see all the links being sent over iMessage.

Exactly, this is what all the other replies saying 'just proxy the client URL call through Apple' are missing. It's not just that the iMessage was encrypted. There's also _why_ it is encrypted in the first place.

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