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Re: Google Accounts Security Vulnerability
From: "Michael J. Gray" <mgray () emitcode com>
Date: Sat, 19 May 2012 12:04:43 -0700

I was not stating that it was a vulnerability in the sense of someone can
compromise your account with only your phone number. I was saying it's not
doing its job in terms of what most people expect it to do.

It provides a false sense of security. It's a security mechanism, it
prevents people from logging onto accounts when they come from a location
that is unrecognized as associated with the account. and it can be
circumvented with little effort on an individual basis. Distributed attacks
would have trouble with it, but could adapt to it. If distributed attacks
are the only component of their threat model, then it's fine. Regardless,
it's interesting and that's why it's here. 


On why I don't want to provide my email address to Google:

It's a different email address which I don't want associated with this email
address for various reasons. That is why I am not going to provide it.

Your assumption that it's a simple piece of information and requires no
effort to give out is correct, but the impact of the association is

The fact that Google can create a test account and reproduce the issue (as I
have now done several times) tells me that they want the account information
for some other purpose or that they're just being lazy.


And as for your last comment related to my "initial point", it's not my
initial point. My initial point was that there's a problem and that Google
should fix it or verify that this is the intended behavior.

I would expect an organization to be able to rig up some tests and sort it
out in a week or so. If Google is doing that, then great.


From: Thor (Hammer of God) [mailto:thor () hammerofgod com] 
Sent: Saturday, May 19, 2012 10:29 AM
To: Dan Kaminsky; Michael Gray
Cc: full-disclosure () lists grok org uk; Mike Hearn
Subject: RE: [Full-disclosure] Google Accounts Security Vulnerability


I tried, and it didn't work (couldn't repro).


None of this matters - if you have username and password, you can check mail
via POP3 or IMAP.   Last time I checked, that was "by design."   If anyone
is saying this is some sort of vulnerability because someone "happens across
your username and password" then they are in the wrong business.


Michael - for you to make these claims, get Google involved, and post their
replies here but refuse to give them your username (which will be on every
email you send out) so they can troubleshoot is really a waste of time.


Your initial point of "even the big companies with teams of security experts
have security vulnerabilities" seems to shrink a bit when they illustrate
concern with the issue yet you refuse to provide the simplest of
information.   I not sure what other expectations one would have of an


Description: Description: Description: Description: Description:
Description: Description: Description: Description: TimSig


Timothy "Thor"  Mullen


27> 's Microsoft Security Bible



From: full-disclosure-bounces () lists grok org uk
[mailto:full-disclosure-bounces () lists grok org uk] On Behalf Of Dan Kaminsky
Sent: Friday, May 18, 2012 1:03 PM
To: Michael Gray
Cc: full-disclosure () lists grok org uk
Subject: Re: [Full-disclosure] Google Accounts Security Vulnerability


Surely you can create a sock puppet for debugging purposes.

On Thu, May 17, 2012 at 11:43 AM, Michael Gray <mgray () emitcode com> wrote:

I'm not interested in providing that information. You can reproduce it
without knowing my user name.

On May 17, 2012 8:45 AM, "Mike Hearn" <hearn () google com> wrote:

If you provide the name of the account you're logging in to, we can go
take a look what's happening.

On Thu, May 17, 2012 at 5:29 PM, Michael Gray <mgray () emitcode com> wrote:
Regardless of how you say it works, I can bypass it every time it would
seem. Again, by using the method in my original post. It's likely you have
bug if this isn't the functionality you're after.

I appreciate the statistics but they mean little to me.

Thank you for taking the time to respond. I hope my suggestions and
will assist you in correcting these issues

On May 17, 2012 5:51 AM, "Mike Hearn" <hearn () google com> wrote:

I understand your concerns, however they are not valid. You can be
assured of the following:

1) We do not see this system as a replacement for passwords. If we
block a login the user is notified and asked if it was them, if it
wasn't we ask them to pick a new password. In very high confidence
cases we will immediately force the user to choose a new password,
because passwords are still the first line of defense.

2) We do not see this system as a replacement for 2-factor
authentication. However the reality is that the vast majority of our
users do not use 2-factor authentication and this is unlikely to
change any time soon. 2SV imposes a significant extra burden on the
user such that despite heavy promotion many users refuse to sign up,
and of those that do, many choose to unenroll shortly afterwards.
Therefore we also provide this always-on best effort system as well.

3) In fact it is very effective at stopping the large, botnet driven
types of attacks we see on a daily basis and so saying it doesn't add
any security is wrong. Since going live the system has successfully
defended tens of millions of users who have a compromised password. A
single unrepresentative data point based on one account isn't enough
for you to judge the utility of the system, whereas we can clearly see
the stopped campaigns (and drop in number of attempts).

That said, if you have friends and relatives who use Google and you'd
like to to make them more secure, by all means encourage them to set
up two-factor authentication.


Mike Hearn | Senior Software Engineer | hearn () google com | Account security

Full-Disclosure - We believe in it.
Charter: http://lists.grok.org.uk/full-disclosure-charter.html
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Full-Disclosure - We believe in it.
Charter: http://lists.grok.org.uk/full-disclosure-charter.html
Hosted and sponsored by Secunia - http://secunia.com/

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