Google researchers discovered a MacOS zero-day exploit being used against Hong Kong activists. It was a “watering hole” attack, which means the malware was hidden in a legitimate website. Users visiting that website would get infected.

From an article:

Google’s researchers were able to trigger the exploits and study them by visiting the websites compromised by the hackers. The sites served both iOS and MacOS exploit chains, but the researchers were only able to retrieve the MacOS one. The zero-day exploit was similar to another in-the-wild vulnerability analyzed by another Google researcher in the past, according to the report.

In addition, the zero-day exploit used in this hacking campaign is “identical” to an exploit previously found by cybersecurity research group Pangu Lab, Huntley said. Pangu Lab’s researchers presented the exploit at a security conference in China in April of this year, a few months before hackers used it against Hong Kong users.

The exploit was discovered in August. Apple patched the vulnerability in September. China is, of course, the obvious suspect, given the victims.