Hackers have targeted Google Chrome users in a frightening attack with dozens of browser extensions compromised with malicious code—here’s what we know so far.

A BleepingComputer investigation found the same code was injected into at least 35 Google Chrome extensions, which are being used by roughly 2.6 million users worldwide. This led to 400,000 devices being infected with malicious code through the CyberHaven extensions.

Criminals have hijacked dozens of popular browser extensions in a bid to target Google Chrome users and steal sensitive data, like passwords. The devastating campaign started last month and shows no sign of slowing.

The attack began after a hacker successfully targeted a Cyberhaven employee via a phishing email that was sent to Chrome extension developers. The employee, believing the email was an official Google contact, clicked the email and input their login credentials on the phishing page.

New details have emerged about a phishing campaign targeting Chrome browser extension developers that led to the compromise of at least thirty-five extensions to inject data-stealing code, including those from cybersecurity firm Cyberhaven.

The publishers of browser extensions on the Google Chrome Web Store were reportedly targeted via a phishing campaign.