E-mails that appear to come from well-known companies and institutions contain viruses.
In accordance with the information we received from Turkey Computer Emergency Response Team (TRCERT), malicious sites are blocked but the website address in phishing mails are changing at every turn. So, the end user should be very careful when receiving e-mails, avoid clicking on links at incoming mail, and avoid downloading files such as EXE, ZIP. When you click on the zip file from that link after downloading it, all word files, images and pdf files become encypted file. Then a file named sıfre_cozme_talımatı.html comes to the desktop and instructions emerging that the person wants money in exchange for your password. Do not open emails from addresses that you don't know the source, do not write your username and password in any way... You can copy of your important files to an external hard drive, flash memory, cloud storage(dropbox, onedrive) offering services you can get backups...
Examples of harmful e-mail is included below.
Mail sample mimicking the PTT institution
Mail sample mimicking the Turkcell institution
Mail sample mimicking the Turk Telekom institution