MicroWorld experts have been intercepting large numbers of PDF spam doing rounds in the last two months, but their volumes surged dramatically since the beginning of July. Leading the pack are two 'Pump and Dump' Scams touting about some stocks in their bid to make you buy them.

The first one is about the stock of a German company called Talktech Telemedia. The well created PDF file looks like a leaf from a trade magazine with its neat design and business language. Like all Pump and Dump scams this one too tells you that, thanks to many positive factors happening in the next few weeks, the price of the stock in question will jump 300%. The second one is also stock related, albeit the PDF here is in a much basic and simpler form.

In Pump and Dump scandals, scamsters buy worthless shares of companies and send out spam mails across the world to drive up their prices. The total number of Talktech spam floating around is estimated to have crossed two billion so far.

A few people bite the bait and the buy the stock going by the 'confidential and profit making' opportunity! Once the stock price picks up, the people behind the scandal just sell their shares off to make huge profits while those who got sucked into the plot lose their hard earned money.

"Earlier, spammers used embedded images in mails to circumvent spam filters that work by checking for specific words and phrases in message content," says Govind Rammurthy, CEO of MicroWorld Technologies. "Many spam filters have now smartened up and they can identify and block such commercial mails. That's why the conmen behind these mass mails are trying out PDF file format to dwindle unsuspecting computer users".

"PDFs are traditionally used for drafting official documents and whitepapers. That's created an air of authenticity and authority about them which would make many drop their guard in downloading the attachment. The faulty perception that PDFs are immune to malware infections helps too," points out Govind Rammurthy.

PDF can carry viruses too as Govind indicates. A Worm named 'Worm.VBS.Peach' in 2001, was found to be propagating by using a PDF file as a carrier while it offered a puzzle game called 'Find the Peach' to the recipients. The Worm stole email addresses from the victim's address book and sent self copies to all email IDs found.

"Many spam filters are giving a slip to these mails while most computers now are equipped with Adobe Acrobat Reader which enables them to display PDF messages. These two factors mean that PDF spam is here to stay for sometime and spammers will continue to innovate in their bid to reach more mail boxes," concludes Govind Rammurthy.

Govind's firm MicroWorld produces advanced AntiVirus, AntiSpam and Content Security software solutions branded as eScan, MailScan, X-Spam. They employ an array of technologies in fighting spam while they also use advanced methods to block image and PDF varieties. MicroWorld's eConceal Firewall provides multiple data filtering and intrusion prevention methods to thwart hacker attacks.