According to the IBTimes (opens in new tab), around five million Google Account credentials have been leaked online by hackers, with around 60 per cent of the compromised accounts judged to still be active.
A user called "tvskit" made the announcement on the Bitcoin Security forum along with a link to the alleged email list. The majority of the leaked accounts seem to belong to Russian users.
The list of email addresses is currently available to download and view in a 100MB text file (packaged in a 36MB zip) on Mega (opens in new tab), and you can use this to see if your address is included. Bear in the mind, the size of the document is very large and so might cause you problems when opening.
You can also check to see if your details have been compromised using the Is Leaked (opens in new tab) portal.
Enter your email address and it will tell you if your information appears in their database. The site says it doesn’t collect your emails nor access logs, but if you’re still suspicious (and rightly so), you can replace up to three characters in your email address with asterisks.
According to the Russia-based CNews (opens in new tab), a Google representative named Svetlana Anurova confirmed the leak saying, "experts now understand what happened in the case" (but added no further details, making it a rather useless quote) and urged users to "select strong passwords and be sure to use two-step authentication".