SophosLabs has intercepted a widespread attack by hackers who have spammed out a Trojan horse posing as an electronic greeting card from a family member.
The emails have the following characteristics:
Subject line: Postcard from a Family Member
Attached file: ecard.zip (which contains a file called ecard.exe)
Part of the email's message body reads:
Your family member has sent you an ecard from 123greetings.com. Send free ecards from 123greetings.com with your choice of colors, words and music. Your ecard will be available with us for the next 30 days. If you wish to keep the ecard longer, you may save it on your computer or take a print. To view your ecard, open zip attached file.
The attached ZIP file, contains a malicious executable file which Sophos detects proactively as Mal/FakeVirPk-A.
Even if you didn't know that hackers were frequently in the habit of disguising their attacks as ecards, you should still have spotted some clues which would have stopped you from opening the attachment. For instance, the sender's address isn't 123greetings.com (although this would have been easy for hackers to have forged if they had wanted to), and the email does not give you any clues as to who the family member is who wanted to send you a greeting card.
But the fundamental lesson is that you should never open unsolicited executable files on your computer. Hackers take advantage of innocent people's curiousity, and can use attacks like this to turn your computer into part of a botnet sending spam, display fake virus warnings designed to con you out of cash, or steal your identity.
Sophos users are already protected, as we were able to proactively prevent this attack from running on computers - but if you use a different vendor's product make sure that it is updated and capable of defending you against this latest malware assault.