PDF spam now makes up for 25% of all spam, according to the latest research statistics from security vendor Marshal.The news poses no surprise to many businesses and individuals that have witnessed the incredibly fast rise in image-based spam, but its early timing might.
Almost two weeks ago, the PDF attachment spam was estimated to have reached around 15% of all spam.
The type of attachments causing the most problems are Excel files, PDFs, text and zip files, the first of which has been seen as one of the latest crazes among spammers.
Last week, spam using attachments only represented 2% of the problem, but this week that figure rocketed to 25%. Marshal claimed that “one core group of spammers” behind the Storm worm were responsible for this week’s surge.
“The latest statistics would suggest that spammers are increasingly using PDF spam over image spam,” said Bradley Antsis, director of product management at Marshal. “However ... the spammers’ experimentation with a range of attachments indicates they are not as confident PDF spam is as effective as image spam was in the past.”
Other research conducted recently has indicated that up to half of the UK’s medium to large sized businesses are genuinely struggling to deal with image based spam. Yesterday, it was revealed that scammers are also using the success of The Simpsons Movie to trick email users into validating their addresses.
