Dozens of universities across China have become victims of a massive global cyber-attack which has affected institutions and businesses in nearly 100 countries.

A ransom note which asks for 300 US dollars in Bitcoin to unlock the files appears on the screen of a computer that belongs to a student from East China’s Hangzhou Normal University [Photo: hangzhou.com.cn]

The attack locks files on a computer and encrypts them, and then demands at least 300 US dollars in Bitcoin to unlock the documents.

According to Avast, a cyber-security company, the ransomware that caused the disasters was identified as WannaCry, reports the BBC.

Cheng, a student from east China’s Zhejiang Gongshang University, said a lot of people are talking about the cyber-attacks on the popular WeChat messaging app, and are complaining that their Word and PowerPoint documents have been locked, according to xinmin.cn.

“As far as I know, academic institutions [in Zhejiang province] such as Ningbo University, Zhejiang Chinese Medical University, Zhejiang Gongshang University and Zhejiang Sci-tech University have been hit by the cyber-attacks,” Cheng said.

Another Chinese university student Tang told xinmin.cn that his computer was hit on Friday night, with a ransom note appearing on the screen saying that if he didn’t pay 300 US dollars in Bitcoin within one week, his files will ever be unlocked.

Tang said the note was in several languages including Chinese, Korean, Japanese and English.

The attack has severely affected many fourth-year university students, as their graduation dissertations have been locked, according to media reports.

Some Chinese universities, such as Dalian Maritime University and Shandong University, have issued notices informing their students about the latest developments, reminding them to install a software patch released by Microsoft for the security holes, and update and backup their systems.

More than 45,000 attacks have been recorded in 99 countries, including the UK, India, Ukraine, Egypt, China, Russia and Italy as of Saturday, according to the Guardian.

The National Health Service (NHS) in the UK has been struck, preventing some hospitals admitting new patients with severe conditions, and many operations have also been canceled, according to media reports.

The attacks take advantage of a vulnerability which was reportedly identified for use by the US National Security Agency (NSA) but subsequently leaked on the internet, according to media reports.