"This may be Microsoft's first public acceptance that this bug is in fact a Microsoft vulnerability," said Andrew Storms, director of security operations at nCircle Network Security. Although Microsoft has not set a timeline for rolling out a patch to plug the hole currently used by RBN's PDFs, Storms bet it would be next month. "It's safe to assume Microsoft will attempt to release a patch in time for the November regular patch cycle," he said.
The next scheduled patch day for Microsoft is November 13, more than two weeks away.
The newest PDF-based exploits, said researchers, are using different subject headings in the spam that delivers the files, and new filenames for the PDF documents. According to F-Secure, the spam messages' subjects now include "Your credit report," "Your Credit File" and "Personal Finance Statement."
Another researcher, Don Jackson of SecureWorks, said that the malware eventually planted on PCs by the RBN attacks is a new variant of Gozi, a Trojan he pegged in February as responsible for the theft of at least US$2 million from bank and credit card accounts.
Gozi then and now works much the same way, Jackson said. Any information entered into a Web page form secured by SSL is nabbed, then sent to the RBM hackers. Virtually every log-on for accessing online bank or brokerage accounts and every major e-tailer order form are secured with SSL, and thus in danger of being stolen by Gozi.
Unlike in February, when RBN carelessly exposed a server containing the stolen data -- which Jackson discovered -- the current attack results are unknown. "They've gotten smarter about where they store their data."
If Jackson is right about the RBN hackers' technical skills, the amount they'll steal this time should prod Microsoft to push out a patch sooner rather than later.
"These guys are good," said Jackson. "They're right up there with the Windows kernel developers as far as programming goes. They're very, very talented. And once they have a foot in the door, they can use that [talent] to force their way in."