Spike in PDF Spam

An Israeli security firm reported a spike in PDF spam earlier this week. This type of spam is a form of image spam where the unsolicited message is embedded in an image sent by e-mail. Traditional spam filters only see an image, not the spam message, and often allow the e-mail through.

This technique has only been seen in the past few weeks, according to the security firm, and is now being distributed by computers in 167 countries.

The discovery is interesting in light of the fact that a recent report by Symantec claims image spam has been declining. Not so, says MessageLabs, another e-mail security vendor.