Once the App has been built with the above permissions, these are the steps to reproduce it:
1. Trojan app contains a WebView that will automatically login into
user’s Google account by requesting authtokens from the Account
Manager, user will not be notified nor have any way to stop this.
2. The WebView will load the Google Play web site and inject
information and CSRF tokens, it will get information about all devices
registered with that account. Remember the browser is logged in with
user’s Google account.
4. Using this information it can issue a request to install ANY app
on Google Play, on EVERY device registered with that Google account.
The Android user or the potential victim will not be prompted at any time for his consent and will not have any way to stop this.
Daniel has also given the likely scenarios once this vulnerability has been exploited by cyber criminals.
– Trojan app could be full screen and the user will not even see the
– Trojan app could choose to install the app on a different device,
from the devices registered with the Google account, the user will not
see anything unusual on the current device where the Trojan runs.
– The installed app can have access to ALL permissions (if it
specifies so in the manifest) without the user explicitly approving
that, it could have access to services that cost you money, like
sending SMS or making phone calls, manage accounts, disable your
phone, just look at the permission list.
– Since you have access to all Google data for that account, there
are other scenarios, like accessing emails and more, but the PoC did
not address those.
Daniel who is a Bug Bounty winner ($2000.00) from Google for his bug report No. 93416 Chromium Security Reward says he has already sent Google with his Proof of Concept for this vulnerability. He has said that since the vulnerability is very high risk therefore he is desisting from publishing the same online at the moment.
“I will not release the PoC, I think it would be too easy to cause real damage. However it is not that difficult to implement.”
The timeline of his reporting to Google about this high risk vulnerability is as follows :
2013-12-16 – Contact security(at)google.com.
2013-12-17 – Received reply that the issues was passed to
2013-12-20 – Received reply that they could not reproduce the issue.
2013-12-20 – Sent a stripped down version of the PoC, not much different.
2014-01-16 – Request status update.
2014-01-24 – Received response that the rollout of the fix started last week.
2014-02-12 – Received response that the fix is live for 100% users/devices.
Daniel says that the fix which has been activated now is, to not allow the browser to automatically login. Instead, the user will be prompted with a text that says it would allow the App to have access to all Google data. This however does not inform the user that it will allow automatic installation of any app, potentially causing direct and immediate loss of money.