Fraudsters are targeting UK schools, demanding payments of up to £8,000 to unlock data they have encrypted with malware.
The online criminals are initially cold-calling schools, claiming to be from the Department of Education.
Once they have email addresses, they forward documents which include file-freezing malware.
UK police issued a warning, urging educational establishments to be vigilant.
The fraudsters claim that they need to send forms directly to the head teacher rather than to a generic school inbox, claiming that the documents contain sensitive information.
The type of forms vary from ones offering exam guidance to mental health assessments, according to Action Fraud, the UK’s fraud and cybercrime centre which issued the alert.
The email will include a zip file, potentially masked as an Excel or Word document. The attachment will contain ransomware that, once downloaded, will encrypt files and demand money to unlock them.
Back to school
Last year was dubbed the year of ransomware by security experts. Kaspersky Labs estimated that in the third quarter of the year a ransomware infection occurred every 30 seconds while Intel Security said that the infections had risen by more than a quarter in the first three months of the year.
Police departments, hospitals and companies have all been targeted, with the FBI declaring ransomware to be on track to become a “billion-dollar criminal enterprise”.
The latest warning shows the threat is not going away, said security consultant Graham Cluley.
“This clearly indicates that there are considerable amounts of money to be made by online criminals through ransomware attacks. If there weren’t, they wouldn’t be prepared to go to such extreme efforts – such as making bogus phone calls – to increase the likelihood that their poisoned email attachments will be opened.”
He said that schools, as well as always being on the lookout for suspicious emails and keeping security software up to date, should also regularly back up critical data.
“If you aren’t backing up your data, it’s you who needs to go back to school,” he said.