Spammers use PDFs to drive up stock prices
Sophisticated spammers allegedly cashed in after using PDFs to drive up stock prices.
In early August, the largest spam spike ever - 445 per cent! - was recorded, according to MX Watch. This incredible flood of spam contained PDF attachments touting stocks for Prime Time Limited, a small Florida company.
This is just the latest example of the growing use of PDFs by spammers. According to Commtouch's Email Threats Trend Report for the second quarter, PDF spam is increasing. The report, which was released July 17, stated during one attack PDFs were part of 10 to 15 per cent of the spam in a 24-hour period. By using a common attachment format, like PDFs, spammers are trying to slip their phishing attacks past defences.
In the Prime Time case, the PDFs worked as people responded with their cheque books. The stock went up 57 per cent (from $.07 to $.11) in what has been described as a "pump and dump scam," an August 13 PC World article stated. In these scams, the perpetrators who have previously bought shares drive up the price and then sell their interest before the inevitable crash occurs. A few days later Prime Time Limited's stocks fell below $.07.
Prime Time Limited has denied involvement in the scam. "Shareholders should be aware that the Company is not the source of any information distributed via bulk e-mail," read a Prime Time press release. "The Company releases information to shareholders on a timely basis, and there are currently no undisclosed material announcements, events or facts with regard to the Company."
According to the Commtouch report, spammers are using PDFs more and moving away from image spam. In the second quarter of 2007, images made up 15 per cent of all spam compared to 30 per cent in the first quarter.
The Commtouch report also revealed spam and viruses have joined forces. The report stated compromised computer networks (botnets) are being used to deliver both spam and computer damaging viruses.
"The same botnets used to spew spam are being used to send malware-infected email," reported Amir Lev, Commtouch President and CTO. "The email-borne malware sent by botnets can steal password and personal data, harvest email addresses and sometimes even launch a distributed denial of service (DDoS) attack. The fact that the same bots are being used for all types of malicious activities is evidence that the enemies have converged."
As for the favourite topic for spammers, pharmaceuticals remained on top. The report stated 45 per cent of spam is pharmaceutical related. Spammers also like stocks (18 per cent) and sexual enhancers (10 per cent).
