An anonymous reader quotes a report from Motherboard: For almost six years, Google knew about the exact technique that someone used to trick around one million people into giving away access to their Google accounts to hackers on Wednesday. Even more worrisome: other hackers might have known about this technique as well. On October 4, 2011, a researcher speculated in a mailing list that hackers could trick users into giving them access to their accounts by simply posing as a trustworthy app. This attack, the researcher argued in the message, hinges on creating a malicious application and registering it on the OAuth service under a name like "Google," exploiting the trust that users have in the OAuth authorization process. OAuth is a standard that allows users to grant websites or applications access to their online email and social networking accounts, or parts of their accounts, without giving up their passwords. "Imagine someone registers a client application with an OAuth service, let's call it Foobar, and he names his client app 'Google, Inc.'. The Foobar authorization server will engage the user with 'Google, Inc. is requesting permission to do the following,'" Andre DeMarre wrote in the message sent to the Internet Engineering Task Force (IETF), the independent organization responsible for many of the internet's operating standards. "The resource owner might reason, 'I see that I'm legitimately on the https://www.foobar.com/ site, and Foobar is telling me that Google wants permission. I trust Foobar and Google, so I'll click Allow,'" DeMarre concluded. As it turns out, DeMarre claims he warned Google directly about this vulnerability in 2012, and suggested that Google address it by checking to see ensure the name of any given app matched the URL of the company behind it. In a Hacker News post, DeMarre said he reported this attack vector back then, and got a "modest bounty" for it.