Google has stopped Wednesday\u2019s 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.\u201cIt looks exactly like the original spoof,\u201d 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 \u201cOpen in Docs.\u201d 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\u2019s attack involved an actual third-party app made with real Google processes. The company\u2019s developer platform can enable anyone to create web-based apps.In this case, the culprit chose to name the app \u201cGoogle Docs\u201d in an effort to trick users.The search company has shut down the attack by removing the app. It\u2019s also barred other developers from using \u201cGoogle\u201d in naming their third-party apps.However, Austin found he could still reproduce Wednesday\u2019s phishing scheme. He did so, by using the search company\u2019s developer platform to create his own third-party app, and also called it \u201cGoogle Docs.\u201dThe only difference is that Austin used a Cyrillic character, used in Russia, for the letter \u201co\u201d in his app\u2019s name.\u201cThe Cyrillic letter o looks exactly like the other letter o,\u201d Austin said. He then replicated the rest of the Wednesday\u2019s attack, creating a fake email that uses the same design interface. \u00a0Austin 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\u2019s attack.\u201cThere\u2019s no question that this will be repeated again,\u201d said Ayse Kaya, a director at Cisco Cloudlock Cyberlabs, a security provider. \u201cIt will probably happen much more often.\u201dMore traditional phishing email schemes can strike by tricking users into giving up their login credentials. However, Wednesday\u2019s attack takes a different approach and abuses what\u2019s known as the OAuth protocol, a convenient way for internet accounts to link with third-party applications.Through OAuth, users don\u2019t 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.[ Related: What is OAuth? How the open authorization framework works ]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\u2019s phishing scheme was that Google\u2019s own services didn\u2019t 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 email@example.com -- a red flag that the product wasn\u2019t real.However, the dummy app still managed to fool users because Google\u2019s own account permission page never plainly listed the developer\u2019s information, unless the user clicks the page to find out, Parecki said.\u201cI was surprised Google didn\u2019t show much identifying information with these apps,\u201d he said. \u201cIt\u2019s a great example of what can go wrong.\u201dRather than hide those details, all of it should be shown to users, Parecki said. \u00a0Austin agreed, and said apps that ask for permission to Gmail should include a more blatant warning over what the user is handing over.\u201cI\u2019m not on the OAuth hate bandwagon yet. I do see it as valuable,\u201d Austin said. \u201cBut there are some risks with it.\u201dFortunately, Google was able to quickly foil Wednesday\u2019s attack, and is introducing \u201canti-abuse systems\u201d 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\u2019s Gmail Android app is also introducing a new security feature to warn users about possible phishing attempts. \u00a0It'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.\u00a0"Hackers have a headstart exploiting this attack," she said. "All companies need to be thinking about this."