South Korea was hit by a massive cyber attack on in March that wiped out hard drives on tens of thousands of computers. Months later, analysts still are dissecting the attacks and where we go from here.
Although who conducted the attacks remains unclear, the McAfee Research Labs research points to clues left behind confirming that the two groups claiming responsibility were a fabrication to throw investigators off the trail and to mask the true source.
McAfee points to the dropper Trojan, which was primarily used to download the executable that destroyed the systems. The firm suspects that the dropper Trojan was distributed at the time of the attacks via a compromised patch-management server that pretended to run a legit update. McAfee also revealed that a MRP wiper and a remote-access Trojan were part of the cyber scheme.
Staying Under the Radar
We asked Tommy Chin, an analyst at CORE Security, to get his take on the issue. He told us South Korea is being targeted for its classified secrets and points their fingers at the North because of how similar the attack patterns were when compared to previous North Korean cyber-attacks. In short, it's military espionage.
"The United States and South Korean military carry out joint exercises every year. This type of classified information can be intriguing to foreign governments to have in their hands. Attempting to plan the exfiltration of this information can be a time consuming process," Chin said. "In 2009, McAfee said that malware was deployed into a social media Web site used by the South Korean military. After years of reconnaissance and spear-fishing attacks, the attackers finally have enough information to draw topology and connectivity of the internal network architecture."
Chin points out that with a successful reconnaissance, the design and implementation of "Operation Troy" was as covert as possible. Attackers were able to design a regular expression engine to locate specific documents that contained concise military related keywords for exfiltration. Another feature to note is how the attackers can select which files to download, he said. This gave them the ability to stay under the radar by limiting network . There was also a second piece of code that wiped hard drives based on anti-virus and anti-debugging detection.
"This implementation of a two-piece Trojan horse is state of the art. Not only does it allow the attackers to quietly perform the exfiltration of military secrets, it also wipes evidence based on the detection of its presence," Chin said. "If a computer not connected to the Internet is the system for classified military secrets, then people must think... How does the data get to this computer to begin with? It is very likely the machine is connected to some kind of internal network and it's pretty obvious the attackers know of an attack path on the inside."
Casting a Wide Net
We turned to Chester Wisniewski, senior security advisor at Sophos, to get his take on McAfee's report. Although he hasn't seen or analyzed the malware in question, he told us it's encouraging to see the South Korean's response, especially the segregation of networks and the 'don't panic!' attitude.
"Malware that looks for certain conditions, whether that be keywords contained in documents or actions being taken by security solutions, is nothing new. Infecting a public social networking site to distribute super-secret government spyware seems more than a touch unlikely as well," Wisniewski said.
"Successful intelligence operations must cast a wide net as we have seen in the NSA dragnet drama. While this could certainly be an intelligence gathering exercise, I think I agree with the South Korean government. Stand down from red alert."