Tech Shout!

According to security firm F-secure, tens of thousands of emails containing malicious PDF files have been flooding the email inboxes of business users since October 26, 2007.

These mails which contain subject lines related to financial information subject lines such as “Your credit report”, “Personal Financial Statement”, “Your Credit File” and “Balance Report.”

The mails do not contain a mail body, but contain an attachment called “report.pdf”, which when opened exploits the CVE-2007-5020 vulnerability in Acrobat Reader and Inter Explorer 7 to further download malware from a server in Malaysia or Sweden.

F-Secure has said that these attacks are dedicated to hijacking the machines with the aim of spreading more malware. Moreover, the security firm is currently in the process of cleaning out the infected servers.

“We’re worried about this case, as PDF attachments are typically not filtered at email gateways. Executable files are now stripped almost everywhere, but PDF is stripped almost nowhere,” said F-Secure’s Chief Research Officer Mikko Hypponen.

“Also, a security update for Acrobat Reader was just made available few days ago, so there are tones of users who haven’t had a chance to update yet,” added Hyponnen.