Re: [rtcweb] ICE exposes 'real' local IP to javascript

* Harald Alvestrand wrote:
>I would see much more benefit in someone trying for a writeup that
>describes precisely the threat they see, what mitigations they see
>against the possible threat, and - importantly - what functionality we
>would lose by implementing those mitigations.
>So far, we've been tossing around the term "private IP address" without
>a precise definition, stating that it is a privacy concern without
>specifying what attacks are possible based on that information, tossing
>around words about possible mitigations (user prompts, browser
>configurations), and not tying those possible mitigations to possible
>loss of functionality (user prompt blindness, lessened usability,
>failures in setting up intra-LAN peer connections). This is not engineering.

Like I said, "If this actually allows random web sites to know that I
am using the addresses,, and
(Ethernet, Wifi, virtual machine) on this computer then that is pretty
much like broadcasting a device GUID" and a fairly persistent one. That
seems reasonably specific to me, and the problems a covertly-obtainable
GUID poses should be clear. It is quite possible many systems offer
fewer bits of identifying information than my configuration, do we have
any scientific research on that?

There are any number of ways to discourage use of this information for
purposes other than those intended, starting with saying that it is not
to be used for other purposes in the specification. User interaction can
be required before sending such information (think file uploads and pop-
up blockers), browsers could indicate when they send the addresses using
some sort of notification so obtaining the information covertly would be
difficult, the API could give sites the option to omit private addresses
to avoid such notifications; sending private addresses could be disabled
if the code is running in some iframe and not the main page. And so on
and so forth. None of this would come with an actual loss of features.

It would also help if we actually had a working draft of the API speci-
fication, the latest one is from 2013 and if it had Security and Privacy
considerations, even the editor's draft for the API has only a "TBD"
Security section.
Björn Höhrmann · ·
D-10243 Berlin · PGP Pub. KeyID: 0xA4357E78 ·
 Available for hire in Berlin (early 2015)  · 

Received on Friday, 6 February 2015 10:55:55 UTC