Researchers said good social engineering and users ’ trust in the convenience afforded by the OAUTH mechanism guaranteed Wednesday ’ s Google Docs phishing attacks Attack.Phishing would spread quickly . Google said that up to 1 million Gmail users were victimized by yesterday ’ s Google Docs phishing scam Attack.Phishing that spread quickly for a short period of time . In a statement , Google said that fewer than 0.1 percent of Gmail users were affected ; as of last February , Google said it had one billion active Gmail users . Google took measures to protect its users by disabling offending accounts , and removing phony pages and malicious applications involved in the attacks . Other security measures were pushed out in updates to Gmail , Safe Browsing and other in-house systems . “ We were able to stop the campaign within approximately one hour , ” a Google spokesperson said in a statement . “ While contact information was accessed Attack.Databreach and used by the campaign , our investigations show that no other data was exposed Attack.Databreach . There ’ s no further action users need to take regarding this event. ” The messages were a convincing Attack.Phishing mix of social engineering and abuse of users ’ trust in the convenience of mechanisms that share account access with third parties . Many of the phishing messages came from Attack.Phishing contacts known to victims since part of the attack includes gaining access to contact lists . The messages claimed Attack.Phishing that someone wanted to share a Google Doc with the victim , and once the “ Open in Docs ” button in the email is clicked , the victim is redirected Attack.Phishing to a legitimate Google OAUTH consent screen where the attacker ’ s application , called “ Google Docs ” asks for access to victim ’ s Gmail and contacts through Google ’ s OAUTH2 service implementation . While the ruse was convincing Attack.Phishing in its simplicity , there were a number of red flags , including the fact that a Google service was asking for access to Gmail , and that the “ To ” address field was to an odd Mailinator account . Google also quickly updated Safe Browsing and Gmail with warnings about the phishing emails and attempts to steal Attack.Databreach personal information . The phishing emails spread Attack.Phishing quickly on Wednesday and likely started with journalists and public relations professionals , each of whom are likely to have lengthy contact lists ensuring the messages would continue to spread Attack.Phishing in an old-school worm-like fashion . OAUTH ’ s open nature allows anyone to develop similar apps . The nature of the standard and interaction involved makes it difficult to safely ask for permission without giving the users a lot of information to validate whether an app is malicious , said Duo ’ s Sokley . “ There are many pitfalls in implementing OAUTH 2.0 , for example cross site request forgery protection ( XSRF ) . Imagine if the user doesn ’ t have to click on the approve button , but if the exploit would have done this for you , ” said SANS ’ Ullrich . “ OAUTH 2.0 also inherits all the security issues that come with running anything in a web browser . A user may have multiple windows open at a time , the URL bar isn ’ t always very visible and browser give applications a lot of leeway in styling the user interface to confuse the user . ”