Spam hasn’t just been an IT security topic of late, it’s been the topic.

Why? Although most spam messages are harmless as long as the end-user knows how to use his or her delete button, spammers are showing quite a bit of innovation in crafting the junk email messages – more so that many virus-writers.

Lately, the most prominent trend has been spammers’ use of attachments to spread messages – mostly, in the past month, PDF attachments.

But those may now be giving way to another type: FDF files.

PDF spam, we hardly knew ye’…

Pedro Bueno, researcher at McAfee Avert Labs, has a rundown posted on the lab’s blog.

“Yes, say goodbye to the PDF spam wave and welcome the FDF stock spam wave! And yes, you will be able to open it with the regular Acrobat reader! Maybe to bypass filters based on file extension, the spam now is using the file extension .FDF, which is the format used by the data exported from a PDF form fields. The new spam will usually follow the format: -UserEmail.FDF, like GlobalTrading-pbueno.fdf.”

- Pedro Bueno, McAfee Avert Labs Blog, Aug. 10, “Goodbye PDF spam…welcome FDF!”