Several cryptocurrency companies have reported an ongoing "supply chain email breach attack" that uses newsletter mailing lists to send malicious phishing links to users. The attack targeted an unnamed vendor that manages mailing lists for crypto companies, and it is currently unclear how much has been stolen. Bitfinex CTO Paolo Ardoino and CoinGecko founder Bobby Ong have confirmed the breach and warned users to be careful with email newsletters in the coming days. Phishing is a technique used by hackers to lure victims into clicking on malicious links, which can drain personal information or give attackers access to online crypto wallets.