We are advising that you beware fake e-mails such as ones pretending to be either from Voicemail, HMRC, image scanners, courier deliveries, company complaints etc, containing small “Zip” attachments.
We’ve been seeing quite of few of these sent to University of Reading recipients. Our antivirus scanners have rejected some of them at the email gateways, but others were only marked as spam, and it’s possible some have leaked through.
The attachments contain malicious Windows programs which are sometimes cunningly disguised to look like sound, document or image files. These in turn download more malware eventually leading to the installation of the infamous CryptoLocker ransomware. This then encrypts all your files and demands a large ransom to recover them.
See http://nakedsecurity.sophos.com/2013/11/16/cryptolocker-urge…for more details
For examples of what the emails may look like, see below: