News of the horrific tornado that hit Monroe, Oklahoma spread rapidly last Monday. So far, this natural calamity left with more than 50 casualties and destroyed neighborhoods in the area. As unfortunate as the incident is, some spammers still took advantage of this event as a social engineering lure.
Trendlabs engineers discovered samples of a spam attack containing invisible ink, a technique using HTML formatting with either white font or a color similar to the mail background, to conceal some words from the reader. Another technique used in this attack is that of HTML Insertion, which embeds words to the comment tags of the mails. The links embedded in these messages lead to aggressive marketing websites. While not exactly harmful, the links themselves could easily have contained or hosted malware.
Users should always be wary of opening email messages, specially from unknown senders.