Pump-and-dump scam causes spam levels to rocket

The campaign, designed to manipulate the share price of a company that sells wireless products, has led to a 30 percent increase in the amount of junk emails detected by the company in the last 24 hours.

The messages are being sent to internet users worldwide with an attached PDF file that urges them to buy shares in a company called Prime Time Group Inc. Investors are unaware that the spammers have already purchased stock at a cheap price, and are now trying to artificially inflate its value by encouraging others to buy more, according to reports. The malicious users plan to then sell off their stock at a profit, which may cause the price to plummet.

Since the rise in spam levels, Prime Time Group Inc. share prices have risen by 60 percent, Sophos said.

"The scale of this stock pump-and-dump spam campaign is like nothing we've seen before, and it looks as though it is working for the cybercriminals behind it,” said Graham Cluley, senior technology consultant for Sophos.

“The share price in this company has rocketed as a result of bogus news being blasted to internet users worldwide. In an attempt to get past anti-spam products, criminals are now regularly using PDF files to carry their slick enticements for potential investors,” he added.

Pump-and-dump stock campaigns currently accounts for approximately 25 percent of the world's spam, according to Sophos.