In the past couple of days, Symantec has observed a spike of email attacks that are designed to distribute malicious threats. All of the observed samples are spoofed to appear as if they are legitimate delivery warnings or notifications from UPS or Post Express. The message text asks recipients to open the zipped executable file for further details or actions necessary to take delivery of the item.
Below are the sample headers observed in this spam attack: From: "United Parcel Service" <info***3@ups.com> From: "UPS� Customer Services"<***@secureserver.net> From: "United Parcel Service" <***@dhl.com> From: "Neil Molina" United Parcel Service <[Details Removed]@ [Details Removed]> From: "Kimberley Miner" United Parcel Service <[Details Removed]@ [Details Removed]> Subject: United Parcel Service notification 40983 Subject: Delivery Status Subject: UPS: Your Package Subject: United Parcel Service notification Subject: United Postal Service Tracking Nr. From: "Post Express Support" <postmail-int[Details Removed]@[Details Removed]> From: "Post Express Information" <postmail-usa. [Details Removed]@[Details Removed]> From: "Post Express Report" <postmail-usa. [Details Removed]@ [Details Removed]> From: "Post Express Office" <postmail-usa. [Details Removed]@[Details Removed]> From: "Post Express Information" <postmail-usa. [Details Removed]@[Details Removed]> Subject: Post Express Office. Package is available for pickup. NR03909 Subject: Post Express Office. Delivery refuse. NR4245855 Subject: Post Express Office. Track your parcel. NR06678 Subject: Post Express Office. Error in the delivery address. NR4061172 Subject: Post Express Office. Get the parcel NR31215 Once the recipient opens the compressed file and executes it, the following threats are installed: UPS tracking number.exe is detected as Trojan.FakeAV. UPS notify.exe is detected as Backdoor.Cycbot. Post_Express_Label.exe is detected as Trojan.Sasfis. A couple of spam samples are shown below:
Symantec analyzed the attacks further and found that the increase in malicious activity, sent from diverse geographical locations, indicates that spammers are working to rebuild their botnets after the Rustock takedown. Symantec recommends that users adhere to the basic practice of not opening or downloading any suspicious attachments from emails such as those described above. Also, install all security patches and keep antivirus definitions up to date to prevent the compromise of personal machines or networks.
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Note: (June 13, 2011) This blog has been updated to better describe the technical aspects of the threats' installation.