Posted by Virus Bulletin on Sep 21, 2011
Increase in malware in spam has not led to increase in malicious activity.
Security researchers have noticed a significant increase in the quantity of spam sent with malicious attachments since the beginning of August; however, they are unclear about the goal of these campaigns.
The campaigns, which we wrote about last month, started to appear in the second week of August. They used various subject lines which, together with the content of the message, led the recipient to believe they had a reason for opening the attachment: a held up parcel, an error on a hotel bill, an account statement etc.
The examples seen by Virus Bulletin all have a ZIP archive attached to the email, with the ZIP containing an executable file; some of these files use unicode tricks to disguise the file extension. The executable, of course, is malicious and a user opening it would find their computer infected with malware.
From posts on end-user forums, researchers at Commtouch found that many users have fallen for these scams. However, they are unsure about the real purpose of the campaigns.
What would be most likely is that the malware is used to send more spam, but spam levels since the beginning of the campaign have remained relatively stable. Other possibilities would be that the malware is used for DDoS attacks or for stealing webmail accounts - but there has been no significant increase in either kind of activity. But, as Commtouch's Avi Turiel suggests, perhaps it will be used for a new kind of evil activity, one "we just haven't heard about yet ([and] maybe we never will)".