A US computer security specialist said Chinese hackers have been exploiting flaws in Microsoft Exchange software.
This has allowed them to steal emails and infect computer servers with code that lets them take control of a computer remotely.
Cybersecurity expert Brian Krebs said: This is an active threat.
Regarding the threat, White House spokeswoman Jennifer Psaki said: Everyone running these servers needs to act now to patch them.
Chinese hackers have targeted US customers (Image: GETTY) We are concerned that there are a large number of victims.
On Tuesday Microsoft released patches to block the hacks.
However, attacks have dramatically stepped up on servers that have yet to be updated.
Кибератака - США заявили об угрозе от Китая после хакерской атаки на Microsoft — новости — УНИАН
unian.net - get the latest breaking news, showbiz & celebrity photos, sport news & rumours, viral videos and top stories from unian.net Daily Mail and Mail on Sunday newspapers.
Добыча, логистика, цены, экспорт - все чем живет угольная промышленность в России и в мире сжато и по делу Всё что влияет на отрасль - в новом партнерском проекте Современного аналитического агентства (CAA) и портала EastRussia — EastRussia
eastrussia.ru - get the latest breaking news, showbiz & celebrity photos, sport news & rumours, viral videos and top stories from eastrussia.ru Daily Mail and Mail on Sunday newspapers.