A nurse in Greater Manchester became one of the first people in the UK to have her files encrypted by a ransomware program that demanded money before it would unlock them.
Users trying to access the files are directed to a new file containing instructions on how to recover the data.
"Do not try to search for a program that encrypted your information - it simply does not exist in your hard disk anymore," the file says. "Reporting to police about a case will not help you, they do not know the password."
The letter also warns people not to report the contact email address unless they want to risk losing touch with the blackmailers and never getting their files back.
However, experts at Sophos have disassembled the Archiveus Trojan, also known
as MayAlert, and recovered the password which is:
"The Arhiveus password is deliberately long and complicated in an attempt by the hackers to avoid people easily cracking it," said Graham Cluley, senior technology consultant at Sophos.
"But now the password has been uncovered, there should be no reason for anyone hit by this ransomware attack to have to make any payments to the criminals behind it."
Cluley went on to warn that internet hackers are getting bolder in their attempts to extort money.
"Most of the viruses and Trojans we see today are being written with the intention of making money," he said.
The first example of ransomware appeared in March 2006, when the Zippo Trojan demanded $300 for the safe return of users' encrypted data.
The Ransom-A Trojan horse appeared the following month threatening to delete stolen files one-by-one until a ransom was paid.
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