Cryptocurrency exchange Coinbase (NASDAQ:) has reportedly suffered another security breach after attackers were able to bypass the company’s multi-factor authentication, or MFA, feature in a coordinated campaign earlier this year.

The attackers stole cryptocurrency from 6,000 accounts, though the monetary value of the theft wasn’t disclosed, As perBleeping computer reported the incident. Coinbase alerted affected customers this week about the theft, which occurred in March and May.