How was ***@gmail.com hacked (and through what? and what is better to do in this situation)?

Question

Computer networks

An attempt to hack into a GMail account
Mail ***@gmail.com (password changed, access restored) There is nothing in the trailer and there is nothing in the mail =)

Yesterday it is 05/16/2015 (that is, yesterday at the time the question was created)
1 login attempt: ip: 31.202 .5.71 05/16/2015 23:01 2 hours after the first login attempt (in Kiev) the provider Maxnet Ltd., Kharkiv Ukraine / itself could not enter from this place 100%
2 login attempt: Ip: 195.88.209.243 05/16/2015 21: 05 (in Kiev) provider Antaro Ltd. Tverskoy district, Moscow, Russia., / I couldn’t enter from this place myself 100% I
punched through the default ports, it seems that it’s not a proxy, at least at the time of the check they didn’t work.

I use laptop, android phone, desktop.
1) as I understood it, or they leaked the database of some site where I had a similar password set and mail was entered.
2) a fake page on which one I got. Well, I always keep an eye on it.
3) some kind of vulnerability desktop or on android. Or applications on android / desktop.
4) some kind of crap from Google itself, because it comes to many (I read it on the net)

Answer 1

Use gmail 2-step authentication - not just a password, but also a mobile phone. Even if the fraudster finds out your password, he will not be able to get to the phone or token.

Answer 2

Never set the password from ask.ru and google the same

Answer 3

An unknown device is a specific user agent.
If there was no binding to the phone, then it will not be difficult to enter.
They already knew the password, just logged in