Google has stopped Wednesday’s clever email phishing scheme,
but the attack may very well make a comeback.

One security researcher has already managed to replicate it,
even as Google is trying to protect users from such attacks.

“It looks exactly like the original spoof,” said Matt Austin,
director of security research at Contrast Security.

The
phishing scheme—which may have circulated to 1 million
Gmail users—is particularly effective because it fooled users
with a dummy app that looked like Google Docs.

Recipients who received the email were invited to click a blue
box that said “Open in Docs.” Those who did were brought to an
actual Google account page that asks them to handover Gmail
access to the dummy app.

While fooling users with
spoofed emails is nothing new, Wednesday’s attack involved
an actual third-party app made with real Google processes. The
company’s developer platform can enable anyone to create
web-based apps.

In this case, the culprit chose to name the app “Google Docs”
in an effort to trick users.

The search company has shut down the attack by removing the
app. It’s also barred other developers from using “Google” in
naming their third-party apps.

However, Austin found he could still reproduce Wednesday’s
phishing scheme. He did so, by using the search company’s
developer platform to create his own third-party app, and also
called it “Google Docs.”

Michael Kan

Security researcher Matt Austin replicated Wednesday’s phishing
attack using Cyrillic script. 

The only difference is that Austin used a Cyrillic character,
used in Russia, for the letter “o” in his app’s name.

“The Cyrillic letter o looks exactly like the other letter o,”
Austin said. He then replicated the rest of the Wednesday’s
attack, creating a fake email that uses the same design
interface.  

Austin has submitted the security issue to Google, and now its
developer platform no longer accepts apps under that name.
However, he and other security experts predict that bad actors
are also working on replicating Wednesday’s attack.

“There’s no question that this will be repeated again,” said
Ayse Kaya, a director at Cisco Cloudlock Cyberlabs, a security
provider. “It will probably happen much more often.”

More traditional phishing email schemes can strike by tricking
users into giving up their login credentials. However,
Wednesday’s attack takes a different approach and abuses what’s
known as the OAuth protocol, a convenient way for internet
accounts to link with third-party applications.

Through OAuth, users don’t have to hand over any password
information. They instead grant permission so that one
third-party app can connect to their internet account, at say,
Google, Facebook or Twitter.

But like any technology, OAuth can be exploited. Back in 2011,
one developer even
warned that the protocol could be used in a phishing attack
with apps that impersonate Google services.

Nevertheless, OAuth has become a popular standard used across
IT. CloudLock has found that over 276,000 apps use the protocol
through services like Google, Facebook and Microsoft Office
365.

What aided Wednesday’s phishing scheme was that Google’s own
services didn’t do enough to point out it came from a
suspicious developer, said Aaron Parecki, an IT consultant who
helps businesses implement OAuth.

For instance, the dummy Google Docs app was registered to a
developer at eugene.pupov@gmail.com—a red flag that the product
wasn’t real.

However, the dummy app still managed to fool users because
Google’s own account permission page never plainly listed the
developer’s information, unless the user clicks the page to
find out, Parecki said.

picture3Cloudlock

The developer behind the fake Google Docs app only appears if
you mouse over the product informaiton. 

“I was surprised Google didn’t show much identifying
information with these apps,” he said. “It’s a great example of
what can go wrong.”

Rather than hide those details, all of it should be shown to
users, Parecki said.  

Austin agreed, and said apps that ask for permission to Gmail
should include a more blatant warning over what the user is
handing over.

“I’m not on the OAuth hate bandwagon yet. I do see it as
valuable,” Austin said. “But there are some risks with it.”

Fortunately, Google was able to quickly foil Wednesday’s
attack, and is introducing “anti-abuse systems” to prevent it
from happening again. Users who might have been affected can do
a Google
security checkup to review what apps are connected to their
accounts.

The company’s Gmail Android app is also
introducing a new security feature to warn users about
possible phishing attempts.  

It’s tempting to install apps and assume they’re safe. But
users and businesses need to be careful when linking accounts
to third-party apps, which might be asking for more access than
they need, Cloudlock’s Kaya said. 

“Hackers have a headstart exploiting this attack,” she said.
“All companies need to be thinking about this.”

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