On Nov 27, 7:42 pm, Adam Barth <[email protected]> wrote:

> It's important to separate two concerns:
>
> 1) Malicious extensions
> 2) Honest extensions that have vulnerabilities (benign-but-buggy)

Absolutely. And I also completely agree with the rest of Adam's post
(below). Just let me add my 2cents - two more advantages to introduce
a `real` protection mechanism for extensions:

1. It would allow Mozilla and the community to inspect more carefully
sensitive extensions (these requiring strong capabilities), for
vulnerabilities (and intentional abuse / trapdoors).
2. It would allow users or user agents to decide whether to install a
specific extension based on its `capabilities profile`. Yes, naive
users may not be able to do this, but sysadmins may define defaults
for an organization, and anti-virus programs etc. can set up such
values.

So, I think this is a good idea. It may require significant work to do
this well, though... but this can be fun!

Best, Amir Herzberg
>
> I agree that the malicious extension problem is somewhat intractable
> because of the above concerns.  However, than news article is
> complaining about vulnerabilities in honest extensions.
>
> In the current extension system, any vulnerability in an extension is
> disaster because every extension runs with the user's full authority.
> That means if I XSS an extension, I can run arbitrary code on your
> machine.  In the DefCon talk, the presenters make this clear by
> installing VNC and remotely moving the user's mouse.
>
> A fortunate fact of the world is that the vast majority of Firefox
> extensions do not require the user's full authority.  (That is the
> statement I have a bunch of data to back up.)  If the extension
> ecosystem let authors restrict the privileges of their extensions (and
> encouraged them to do so), then vulnerabilities in extensions would be
> less severe because the attacker would obtain less that the user's
> full authority by compromising an extension.
>
> > The only solution to this problem, IMO, is to authenticate authors, not
> > code. If you know who the author is, to a sufficient level that there's some
> > chance of a policeman feeling his collar if he turns out to have written
> > code which steals all your passwords, then there's an incentive for good
> > behaviour. (This is how EV SSL certs work.) Of course, this works against
> > "anyone can author an add-on and put it on the web and have people use
> > it"...
>
> For the benign-but-buggy threat, the authors are perfectly nice
> people.  No amount of authenticating them is going to reduce the
> severity of vulnerabilities in their extensions.
>
> Adam

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