A PDF spam that was released by spammers using blurred/distorted text has been identified by an anti-spam software developer according to an article at The Register’s website.

It is “”a kind of Turing test for spam filters,” said Neil Cook. He is a European anti-spam specialist for a company called Cloudmark.

“We’ve been seeing a lot of PDF stock spams for the last 10 days or so, and there was another spike last night. Images are particularly easy for humans to pick up, but particularly hard for computers,” he added.

The fingerprinting technology has managed to stop these kind of PDFs for now claimed Cook. This means that most of the population will receive these kind of spam.

Source: The Register