Spam encrypted over the filter system

Using encrypted attachments is the latest technique to bypass the content filtering system of spammers. E-mail service provider Email Systems warns that this technology is becoming more and more widely used.

New attack techniques are based on a weakness in content filtering systems. It is these systems that cannot scan content in emails that contain encrypted or password-protected attachments. If there is no blocking solution, most emails like this will be allowed to enter the user's mailbox.

In recent times Email Systems has recorded relatively rapid growth in the number of such email types sent from systems that have been kidnapped by hackers. These emails often contain a compressed file hiding the famous spam-sending trojan Storm.

Recipients of such emails can easily find the password to extract the attachment because they are already placed in the content of the email. Often the password will be set in the form of sentences that are most likely to attract the user's attention.

Although the technique has been around for a long time, the spammer has just begun to apply widely, said Greg Miller, an expert at Email Systems.

The appearance of new spam attack technique is a completely understandable thing since most of the "spammers" of spammer such as image spamming have been found by the security community.

Hoang Dung