In a blog published today, the researchers outlined their methods for finding the email, and offered a likely theory on how the security giant might have been infected.
"The current theory is that a nation-state wanted to break in to Lockheed-Martin and Northrop-Grumman to steal military secrets," the blog says. "They couldn't do it, since these companies were using RSA SecurID tokens for network authentication. So the hackers broke into RSA with a targeted email attack. They planted a backdoor and eventually were able to gain access to SecurID information that enabled them to go back to their original targets and succesfully break in."
In April, RSA disclosed the fact that the breach was caused by an email attachment, F-Secure explains, but it did not release the file and no one in the research community had seen it. But F-Secure researcher Timo Hervonen kept digging, and eventually found the file in the Virus Total cache.
In fact, Hervonen not only found the file, but the original email that infected RSA. "It was an email that was spoofed to look like it was coming from recruiting website Beyond.com," the blog says. "It had the subject '2011 Recruitment plan' and one line of content: 'I forward this file to you for review. Please open and view it.' The message was sent to one EMC employee and cc'd to three others."
F-Secure posted a video which shows what happens when the email is opened. "In this video you can see us opening the email to Outlook and launching the attachment," the blog says. "The embedded flash object shows up as a [X] symbol in the spreadsheet. The Flash object is executed by Excel [why the heck Excel supports embedded Flash is a great question].
"The Flash object then uses the CVE-2011-0609 vulnerability to execute code and to drop a Poison Ivy backdoor to the system," the blog continues. "The exploit code then closes Excel and the infection is over." Poison Ivy links the exploit back to a malicious server, F-Secure explains.
"Once the connection is made, the attacker has full remote access to the infected workstation," the blog states. "Even worse, it has full access to network drives that the user can access. Apparently, the attackers were able to leverage this vector further until they gained access to the critical SecurID data they were looking for."
The email attack is not particularly complex, F-Secure says. "In fact, it's very simple. However, the exploit inside Excel was a zero-day at the time, and RSA could not have protected against it by patching their systems."
Have a comment on this story? Please click "Comment" below. If you'd like to contact Dark Reading's editors directly, send us a message.