Russia’s biggest internet portal and email provider Rambler.ru, also known as Russia’s Yahoo, suffered a massive data breach in 2012 in which an unknown hacker or a group of hackers managed to steal nearly 100 Million user accounts. The leaked user records included usernames, email addresses, ICQ numbers (IM chat service), social account details, passwords and some internal data. None of the passwords were hashed, meaning the company stored its user’s password in an unencrypted plain text format that could allow hackers to see passwords easily.
Source: https://thehackernews.com/2016/09/russias-largest-portal-hacked-nearly.html