One of the unfortunate realities of the Internet today is a phenomenon known in security circles as “credential dumps”—the posting of lists of usernames and passwords on the web. We’re always monitoring for these dumps so we can respond quickly to protect our users. This week, we identified several lists claiming to contain Google and other Internet providers’ credentials.We found that less than 2% of the username and password combinations might have worked, and ourautomated anti-hijacking systems would have blocked many of those login attempts. We’ve protected the affected accounts and have required those users to reset their passwords.It’s important to note that in this case and in others, the leaked usernames and passwords were not the result of a breach of Google systems. Often, these credentials are obtained through a combination of other sources.For instance, if you reuse the same username and password across websites, and one of those websites gets hacked, your credentials could be used to log into the others. Or attackers can use malware orphishing schemes to capture login credentials.
We’re constantly working to keep your accounts secure from phishing, malware and spam. For instance, if we see unusual account activity, we’ll stop sign-in attempts from unfamiliar locations and devices. You canreview this activity and confirm whether or not you actually took the action.
A few final tips: Make sure you’re using a strong password unique to Google. Update your recovery options so we can reach you by phone or email if you get locked out of your account. And consider 2-step verification, which adds an extra layer of security to your account. You can visit g.co/accountcheckupwhere you’ll see a list of many of the security controls at your disposal.
Posted by Borbala Benko, Elie Bursztein, Tadek Pietraszek and Mark Risher, Google Spam & Abuse Team
Media reports yesterday suggested that Gmail login data for 5 million accounts had been leaked online, but there was no evidence that Google itself had been hacked. Here is Google’s statement in response to the incident: