A widespread scam affecting Google Docs began to land in users’ inboxes on Wednesday in what has been described as a sophisticated phishing campaign.

The scam works by inviting users to edit a Google Doc – the company’s popular app for writing and sharing files. The email subject line states that a contact “has shared a document on Google Docs with you”. Once users click the “Open in Docs” button, it takes them to a legitimate Google sign-in screen that then asks to “continue to Google Docs”.

If a user then clicks on that link, it grants permission to a bogus third-party app to potentially access contacts and emails.

The news of this scam comes just days after Google and Facebook confirmed they fell victim to a $100m phishing scam dating back to 2013.

This latest Gmail phishing attack does not come as a surprise – it’s another prime example of a phishing attack using a personal email to bypass corporate filters. We’ve seen malware adapt to improving detection by switching tactics, and we can expect that phishing campaigns will resort to sophisticated, personalized social engineering tactics to bypass technical and human detection.

In this particular instance, the key takeaway is that the attack uses low-risk file viewing activity to lure users to enter credentials whose reach is broad due to federated identity. Increasing reliance on connected cloud services makes more information (both business and personal) available by compromising a single shared logon.

Banks forced secure and multi-factor authentication to their services a long time ago – a measure that greatly complicates the abuse of stolen credentials. Google does offer comprehensive, easy to use multi-factor authentication options that would stop re-use of account credentials if stolen. Consumers should use the multi-factor authentication for Gmail and all important internet services where they store important personal and business information to protect their sensitive information.

Moving forward, we expect to see a broader range of phishing campaigns using messaging apps and social media to bypass corporate filters, it’s more important than ever that user awareness training and education moves up the priority list to make people an effective part of the kill chain.