Several cryptocurrency businesses are reporting that there is an ongoing “supply chain email breach attack” that uses newsletter mailing lists to send malicious phishing links to users.

The breach targeted an unnamed vendor that manages mailing lists for crypto companies. Bitfinex CTO Paolo Ardoino and CoinGecko founder Bobby Ong have confirmed that a breach has taken place.

“There is an ongoing supply chain email breach attack happening with an email newsletter vendor right now,” Ong said. “Several crypto companies may be affected via email blasts of fake token launches. Be careful with email newsletters in the coming days.”

"We have received two independent confirmations that a prominent vendor used by crypto companies to manage mailing lists might have been compromised. "Please beware of any emails suggesting crypto-airdrops received more than 24 hours ago," Ardoino. added.

Phishing is a technique used by hackers to lure a victim into clicking on a malicious link. That link will either drain that user’s personal information, like login data, or it can link directly to an online crypto wallet, giving the attacker access to the user’s wallet.

The amount, if any, that has been stolen from phishing links in connection with this breach is currently unclear.