Each of us heard about dangerous viruses attached to the mail. The Trojan, which had been sent to the mailboxes, blocked the access to the data stored on the user's hard drive. 

One of the Polish printing houses was the victim of the similar attack. The entire case was described by TV Polsat news programme - Wydarzenia. 

With one click, the company lost 20 years of their work. Additionally, the  cybercriminals demanded the ransom for decoding the files.  

The message with the attached invoice was sent to the company's mailbox. By clicking the attachment the employee installed the virus created by cybercriminals. From that moment on, the employees of the printing house could only see the message informing them that all files including photos, films and documents  had been encrypted by the specially created virus. 

The printing house lost projects and the archives of books collected throughout 20 years. 

A proposal was put forward, the cybercriminal promised  that for 20 thousand they  would decode the files. The owners of the printing house  decided not to pay the ransom, and made the case public just to warn the others. 

Lets bear in mind, there is no guarantee that the files will not  be encrypted again. 

There is no way to be completely protected against this kind of attacks. However, it is always a good idea to create backup of the important files.