The electronic sports network ESEA was apparently hacked in December after owners refused to pay a $50,000 ransom.
The leak affects over 1.5 million users of the network who were informed about it on December 30th.
ESEA posted on Twitter over the weekend to say "We have been working around the clock to further fortify security and will bring our website online shortly when that next round is complete."
The network has advised users their details may have been compromised in the hack, with leaked details including; usernames, first and last names, email addresses, dates of birth, phone numbers, Steam IDs, Xbox IDs, PSN IDs and bcrypt hashes.
ESEA users on Reddit confirmed that player information was discoverable in the leaked data.