Security researchers have finally found the file used to hack RSA's systems, some five months after the security firm was infiltrated in what it described as an advanced persistent threat (APT) attack which compromised its SecurID token system.
RSA was forced to offer all of its 20,000-plus enteprise customers new SecurID tokens after the breach, which is believed to have been carried out by hackers in order to break into Lockheed Martin and Northrop Grumman to steal military secrets.
F-Secure chief research officer Mikko Hyppönen explained in a blog post that the Outlook message file was found by his colleague Timo Hirvonen after an exhaustive search.
It revealed the original phishing email used to trick an employee of EMC, which owns RSA, into opening a booby-trapped Excel spreadsheet.
"It was an email that was spoofed to look like it had come from recruiting web site Beyond.com," said Hyppönen.
"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."
On opening the attachment, a Flash object was executed by Excel which used the CVE-2011-0609 vulnerability to execute code and drop a backdoor known as Poison Ivy, before closing down Excel, Hyppönen explained.
Poison Ivy then connected back to the attack server, allowing the hacker full remote access to the infected workstation and any network drives.
The revelation highlights the importance of staff awareness training and the relative simplicity of the social engineering email.
However, it also excuses RSA to an extent because, while the method of attack was fairly simple, the exploit itself was a sophisticated zero-day threat which the firm could not have deflected by patching its systems, according to Hyppönen.
"Was this an advanced attack? The email wasn't advanced. The backdoor they dropped wasn't advanced. The exploit was advanced. The ultimate target of the attacker was advanced," he said.
"If somebody hacks a security vendor just to gain access to their customers' systems, we'd say the attack is advanced, even if some of the interim steps weren't very complicated."
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