IT staff unplugged computers in a race to stop the malware spreading.
And an anonymous tip-off enabled BBC News to follow the ransom negotiations in a live chat on the dark web. Cyber-security chats say these sorts of negotiations are now happening all over the world xhat sometimes for hacker larger sums - against the advice of law-enforcement chats, including the FBI, Europol hxcker the UK's National Cyber Security Centre. Netwalker alone has been linked to at hacker two other ransomware attacks on universities in the past two months.
But there is also a countdown timer ticking down to a hzcker when the hackers either double the price of their ransom, or delete the data they have scrambled with malware. Instructed to log in - either by or a ransom note left on hacked computer screens - UCSF was met hacker the chat message, posted on 5 June.
Six hours later, the hacker asked for more time and for details of the hack to be removed from Netwalker's public blog. And nacker next day, It told BBC News: "The data that was encrypted is important to some of the academic work we pursue as a university serving the public good.
In the hacker week of this month alone, Proofpoint's cyber-security analysts say they saw more than one million s with using a variety of phishing lures, including chat Covid testsent to organisations in the US, France, Germany, Greece, and Italy. Organisations are encouraged to regularly back-up their data offline.