oss-sec mailing list archives

Re: CVE Request - Coin Widget serves code over plain http.


From: Kurt Seifried <kseifried () redhat com>
Date: Tue, 30 Jul 2013 00:18:21 -0600

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On 07/28/2013 06:07 PM, Christey, Steven M. wrote:
Kurt Seifried said:

The problem is not in the code, the problem is in how the code
is served/distributed. CVE is traditionally for software and not
for services. So under a simplistic reading of that strict
definition I would say this doesn't deserve a CVE.

tl;dr I've looked into this issue some more and in general, I
agree.

I suspect there are a couple issues here; note that these are some
of my impressions and not anything "official" from CVE:

1) The downloading and execution of code from an "http://"; URL is
subject to various attacks, including DNS spoofing and MITM.  To my
way of thinking, the main issue is that the code is not downloaded
in a way that preserves its integrity AND ensures that it was
downloaded from a trusted source.  For CVE, a core question for
inclusion is, "does this download of code WITHOUT an integrity
check (CWE-494) happen automatically, or is there a documented
manual step in which the administrator is expected to verify the
integrity?"

2) With Coin Widget in particular, the widget is available in
github, and people can download the code and install it on their
own servers (see the "Download the Source Code" link from the main
page at http://coinwidget.com/).  Thus Coin Widget can be offered
as a customer-controlled "product" (not just a service) and, as a
product, could qualify for a CVE, but read on...

3) However, from http://coinwidget.com/, it appears that the Coin
Widget installation documentation tells the installer to modify
widget/coin.js to point to an admin-controlled source.  This
suggests that it's an admin-controlled configuration, which may
exclude it from CVE.

4) The "Wizard" that generates Coin Widget code for people is out
of scope - this is inherently "site-specific" in that there would
be no customer actions to fix a vulnerability; the Coin Widget
admins could modify their code to avoid use of http:// URLs
entirely, without any action on behalf of customers.

5) One could argue that this issue is due to a fundamental problem
in HTTP, and as such, HTTP should be "blamed" for not having
integrity checks; but, to assign a CVE to every commonly-used
protocol that doesn't use encryption is not necessarily
appropriate, either.

All in all, for now, it seems to me that this particular Coin
Widget issue is out of CVE's scope because of the
software-as-a-service and configuration considerations, but the
general issue of "reading and executing scripting code from http://
links without verification" may qualify.

So like CVE-2009-3555 we have a single CVE for the issue and any
future instances can be submitted to cve-assign@ for addition? Problem
is this CVE would become monstrously huge and unwieldy.

However the world is changing, for example a program that
included an auto-updater component that was advertised as being
"Secure" but went over HTTP would probably qualify for a CVE.

It probably would, but since this might theoretically affect any
software that's 5 years old or more and downloads anything over
unencrypted channels without integrity checks, the raw number of
CVEs that could be assigned is rather daunting.

Yup. Maybe only apply it to common software/software that advertises
"Secure" updates? Seems like a cop out (I vote we do it right or not
at all, but first define what "right" is =).

Steve I'm bouncing this to you, I'm inclined to NOT assign a CVE
since it opens up a huge can of worms (every single bit of
JavaScript served from HTTP and not available via HTTPS ever),
but I can also see how it should maybe get a CVE.

My gut reaction is that you might be treating this as a more
complex issue than it really is.  Simple delivery of code over HTTP
might affect Coin Widget and many other packages, regardless of
whether *some* code is delivered over HTTPS.

One thing I've been thinking about is all the software on the planet
that I have no real clue as to how secure/well developed it (to say
nothing of how well a packager like
Fedora/Debian/Ubuntu/Dreamhost[1]/etc cares for it). Some signals
exist, like do they have a security@ contact that actually replies? Do
they have a bug tracker? Do they offer updates? Did they set static
SSH host keys? In general we have no way of knowing, perhaps
OSVDB/someone wants to start collecting data on known good and known
bad software projects in addition to vulnerability info (e.g. has
"bugtracker, URL is at, bonus point for supporting security bugs that
are private)"? But then the legal issues "you said something mean
about us so we're taking you to court in the UK for libel" come up and
I basically give up since I have no answer for that one =).

[1]
http://missingm.co/2013/07/identical-droplets-in-the-digitalocean-regenerate-your-ubuntu-ssh-host-keys-now/

The good news is that future versions of Firefox are implementing
a security policy that when loading a page from HTTPS they will
not load page components from HTTP, which would fix this issue.
Hopefully all the browsers do this.

While there are no formal rules, CVE generally considers "typical
behavior of market-leading browsers" as acceptable considerations
for determining a vulnerability; e.g., many XSS attack variants
only apply to 1 or 2 browsers.

- Steve

- -- 
Kurt Seifried Red Hat Security Response Team (SRT)
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